For U.S. consumers, a police report usually isn't required before disputing an unauthorized transaction. A bank or card issuer generally needs enough information to identify the transaction, understand why you say it wasn't authorized, and investigate the account record. The most useful submission is usually a prompt notice, a short timeline, and records that match the facts.

The process depends on how the payment moved:

• Credit card charge: Usually handled as a billing error under the Fair Credit Billing Act (FCBA) and Regulation Z.
• Debit card, ATM, ACH, prepaid card, or another electronic fund transfer: Often handled under the Electronic Fund Transfer Act (EFTA) and Regulation E.
• Payment app or wire transfer: Coverage depends on the account, transfer method, and provider agreement.

Notify the financial institution as soon as you spot the transaction. For a credit-card billing error, written notice must generally reach the issuer within 60 days after the statement containing the error was sent. For a debit or other electronic transfer, prompt notice can limit liability, particularly if a card or access device was lost or stolen.

The evidence a dispute normally needs

There is no single federal document checklist for every unauthorized-transaction claim. Your notice should let the institution locate the transaction and understand the basis of the dispute.

Include:

1. Your name and account information. Give the account number or card number ending in the last four digits. Don't send a full account number through ordinary email.
2. The transaction details. State the merchant or transaction description, date, amount, currency, and reference number if one is available.
3. A direct statement that you didn't authorize it. Say that you did not make or authorize the transaction. Be accurate if an authorized user, household member, employee, or another person with access to the card, device, PIN, or account could have made it.
4. When you noticed the transaction. This helps establish whether your notice was timely.
5. The relevant timeline. Include the last legitimate use, the date a card or device was lost if applicable, when you contacted the institution, and the security steps you took.
6. Records that fit what happened. Depending on the facts, these might include a statement, app screenshot, fraud alert, account-login notice, replacement-card confirmation, merchant email, or record showing you were elsewhere.

The FTC's guide to disputing credit-card billing errors describes the information to include in a written credit-card dispute. Under 12 CFR section 1026.13, an unauthorized extension of credit can qualify as a billing error when it wasn't made by the consumer or someone with actual, implied, or apparent authority to use the account.

Documents that may strengthen the claim

These items can help, but none is automatically required for every dispute:

• Police report: Useful after physical theft, identity theft, or repeated fraudulent activity. It shouldn't delay your initial notice.
• FTC Identity Theft Report: Useful when someone used your personal information to open or access accounts. The FTC's identity theft guidance explains the recovery process.
• Witness statement: A signed statement may support facts about who had the card or phone. It usually works best alongside account records and a consistent timeline.
• Location or travel records: Work records, travel bookings, or similar documents can support your account of what happened. They don't prove on their own who authorized a transaction.
• Merchant correspondence: A merchant's statement that it can't match an order to your account may help. A delivery record, however, generally shows delivery rather than authorization.
• Bank or merchant fraud data: Device fingerprints, IP addresses, digital-wallet token details, authentication records, and geolocation data are usually held by the bank, merchant, or payment network. You generally don't need to obtain them yourself. Ask the issuer to review them when they are relevant.

An IP address associated with another city or country isn't conclusive. Mobile networks, shared connections, travel, and virtual private networks can make location data misleading. Don't claim to have seen evidence that the bank or merchant hasn't provided.

Confirm the payment rail before you dispute

The logo on a card doesn't determine every legal right. A debit card with a Visa or Mastercard logo is generally still a debit-card electronic fund transfer, not a credit-card FCBA claim.

Business accounts and some transfers don't receive the same protections as consumer accounts. If the classification is unclear, notify both the provider and the linked financial institution. Ask which error-resolution process applies and whether the institution needs a separate written notice.

A chargeback is generally a card-network and issuer procedure, not a guarantee of reimbursement. For a credit card, send the formal FCBA billing-error notice even if the issuer also opens a network chargeback. For a debit transaction, a chargeback workflow doesn't replace notice required under Regulation E.

Put the evidence in a usable order

A reviewer can work faster from a short, labeled packet than from a folder of unrelated screenshots.

1. Save the transaction record

Keep the statement page, downloadable statement, or banking-app screen showing:

• Merchant or transaction description
• Amount and currency
• Transaction date and posting date
• Card or account ending digits
• Transaction or confirmation number

Keep the original file or screenshot. If you redact information for submission, retain an unedited copy in a secure location.

2. Make a fact-based timeline

Use dates and events rather than conclusions:

Add facts that explain the sequence, such as when a phone was stolen, when an unfamiliar login appeared, or whether the physical card stayed in your possession.

3. Keep facts separate from guesses

You can state that:

• You didn't make the purchase.
• You didn't give anyone permission to use the card or account.
• The physical card was in your possession, or it was lost on a specified date.
• You changed your password after receiving an account alert.

Don't say that a particular IP address or device made the transaction unless the bank or merchant gave you that information.

4. Label and protect the attachments

A simple index might look like this:

• Attachment 1: Statement showing the disputed transaction
• Attachment 2: Timeline
• Attachment 3: Fraud alert or card-freeze confirmation
• Attachment 4: Merchant correspondence
• Attachment 5: Police or FTC identity-theft report, if applicable

Redact Social Security numbers, full card numbers, passwords, security answers, and unrelated account activity. Use the bank's secure upload system or the submission method specified for billing disputes.

Steps to take after finding the transaction

1. Rule out a misleading description

An unfamiliar merchant name may be a billing descriptor, digital-wallet transaction, subscription renewal, or purchase by an authorized user. Check receipts, email, wallet history, and household or employee access before calling the transaction fraud.

If you approved the purchase but the product was defective, never arrived, or was charged after cancellation, the issue may be a merchant or billing dispute instead. Use the most accurate reason. A transaction shouldn't be described as unauthorized simply because the purchase went wrong.

2. Secure the account

Call the issuer or bank using the number on the card, statement, or official app. Ask whether it can:

• Freeze or replace the card
• Block additional transfers
• Review other recent transactions
• Secure online banking or mobile access
• Remove an unfamiliar digital-wallet device
• Explain whether passwords, PINs, or authentication credentials need to be changed

Changing a password doesn't establish that the original charge was unauthorized, but it can help prevent additional losses.

3. Report the exact transactions

Record the date and time of the call, the representative's name or ID if provided, the case number, any document deadline, and whether provisional credit was issued.

For a credit-card billing error, send a written dispute to the billing-inquiries address on the statement. That address may be different from the address used for payments. The FTC guidance recommends keeping a copy and sending the letter so the issuer receives it within 60 days.

For a Regulation E claim, oral notice may start the error-resolution process. Written follow-up gives you a clearer record. Ask whether the institution requires written confirmation after an oral report and where it must be sent.

4. Send a focused dispute

You can use this structure:

Subject: Dispute of unauthorized transaction

I dispute this transaction as unauthorized: [merchant], [date], [amount], account ending in [last four digits].

I did not make or authorize this transaction. [Add accurate facts about possession of the card, a lost device, or an unfamiliar account login.]

I noticed the transaction on [date] and notified the institution on [date]. I have secured the account and reviewed the surrounding transactions.

Please investigate the transaction and send me the written result. The attached documents are: [numbered list].

For a credit-card claim, make sure the notice reaches the issuer's billing-dispute address within the 60-day period. Don't rely on an old form that demands a 45-day resolution. The FCBA resolution period is generally two complete billing cycles, but no more than 90 days.

5. Use identity-theft and police reports when they fit

Use the FTC's identity-theft reporting process if someone used your personal information, opened an account, or accessed more than one financial service. A police report can be useful after physical theft or when the bank or local law enforcement requests one.

Neither report should hold up the first notice to the bank. Send the report later if it becomes available.

6. Follow the investigation

Keep the dispute letter, delivery confirmation, screenshots, call notes, bank messages, and provisional-credit notice together. Continue checking for related transactions.

Provisional credit on a debit account may be reversed after the investigation. Treat it as temporary until the institution sends its final determination.

With a credit card, keep paying undisputed charges and follow the issuer's instructions about the disputed amount. Don't stop making every payment because one charge is under review.

Deadlines that matter

Credit-card disputes under the FCBA

• 60 days: Written notice must reach the issuer within 60 days after the first statement showing the billing error was sent.
• 30 days: The issuer generally must acknowledge the dispute in writing within 30 days, unless it resolves the issue sooner.
• Two billing cycles or 90 days: The issuer generally must resolve the dispute within two complete billing cycles, but never more than 90 days.
• Payments during review: You generally can withhold the disputed amount while the issuer investigates, but pay undisputed amounts and follow the billing instructions.

The 60-day notice period isn't the same as a promise of zero liability. Federal limits, issuer terms, and network policies can affect the final amount. Some issuers offer protections broader than the federal minimum, so check the card agreement.

Debit and other electronic transfers under Regulation E

• Two business days: If you learn that a debit card or access device was lost or stolen, reporting within two business days generally provides the lowest statutory liability exposure.
• 60 days: If an unauthorized electronic transfer appears on a statement, report it within 60 days after the statement was sent. Waiting longer can increase liability for later transfers.
• Initial investigation: The institution generally has 10 business days to investigate or provide provisional credit under the applicable process.
• Extended investigation: When provisional credit is provided, the investigation can generally extend to 45 days. Longer periods may apply to certain new-account, point-of-sale debit, or international cases.

These aren't universal network chargeback deadlines. Visa, Mastercard, and other payment networks have internal limits that vary by transaction type and dispute reason. An issuer may also set a shorter customer-submission deadline, so ask for the exact date when you open the claim.

Why an unauthorized-transaction claim may be denied

Only the merchant was contacted. A merchant complaint doesn't necessarily notify the bank or card issuer under the applicable law. Contact the financial institution directly, even if you also ask the merchant for a refund.

The notice was late or sent to the wrong address. For a credit card, sending a letter to the payment address or waiting for a phone investigation can jeopardize the formal billing-error process. Use the billing-inquiries address and keep proof that the notice arrived.

The charge was unfamiliar rather than unauthorized. A different descriptor, recurring subscription, digital wallet, or authorized user may explain it. Check those possibilities first.

The notice lacks transaction details. “I don't recognize this” is less useful than the amount, date, merchant description, account information, discovery date, and facts explaining the claim.

The timeline doesn't make sense. Explain the situation if the card was used before you reported it missing, another person had access, or several transactions occurred over multiple days. Contradictions can cause the institution to question the claim.

A police report was treated as a prerequisite. A report can support the claim, but waiting for one can cause you to miss a notice deadline.

An IP address was treated as conclusive. IP and device records can support an investigation, but they can be incomplete or misleading. Ask the institution to review its internal authentication and device records instead of relying on speculation.

If the institution denies the dispute

Request the written decision and ask:

• Why the transaction was treated as authorized
• What transaction evidence the institution relied on
• Whether it classified the matter as unauthorized use, a merchant dispute, or another claim type
• How to request reconsideration or appeal, and the deadline
• Which documents it says are missing

For a credit-card billing error, the rule requires an explanation when the creditor concludes that no error occurred. Ask for supporting documentary evidence where the rule makes it available.

Respond to the stated reason for denial. If the institution says an authorized user made the purchase, explain who had access and whether permission existed. If it points to delivery, explain why delivery doesn't establish authorization. Submit new, relevant evidence rather than repeating the same unsupported statement.

If the institution failed to follow the applicable notice or investigation process, or won't explain its decision, contact the regulator that supervises it. The Office of the Comptroller of the Currency complaint page covers national banks and federal savings associations. For another type of institution, check the bank's disclosures or website to identify its regulator.

A regulator complaint doesn't guarantee a refund and doesn't replace the original dispute deadline. Keep the bank's internal dispute open while the complaint is reviewed.

This information is for U.S. consumers and is general educational information, not legal advice. If you spot an unfamiliar transaction, save the statement, call the right institution today, and send a concise written notice before the applicable deadline.

Sources and rules

• FTC: Using Credit Cards and Disputing Charges
• 12 CFR section 1026.13: Billing error resolution
• Regulation E error-resolution overview
• FTC: What To Know About Identity Theft
• OCC: File a Complaint