You don't need lawyer letterhead to fight an unauthorized bank charge. You need the transaction facts, a clear line that you did not authorize the transfer, and written notice that arrives before the federal deadline runs.

Already called the fraud line? Still put it in writing.

Verbal reports can freeze a card in minutes. They often fail later as proof of the date you notified the bank, the exact charges you meant, and the fact that you called those charges unauthorized rather than a merchant refund request.

Thing is, credit and debit are not the same dispute. The Fair Credit Billing Act covers credit billing errors. Regulation E error-resolution procedures cover debit cards, ATM withdrawals, and most ACH pulls from a consumer account. Cite the wrong framework and you may demand a timeline the bank does not owe on that product.

Copy this unauthorized transaction letter

Use this as a draft. Put your facts in. Cut any sentence that does not fit the account.

[Your name]
[Your mailing address]
[City, State ZIP]
[Phone]
[Email]
[Date]

[Bank or card issuer name]
[Error-notice or billing-inquiries address from your statement]
[City, State ZIP]

Re: Unauthorized transaction dispute
Account ending in [last four digits]
Account type: [credit card / debit card / checking ACH]

I am writing to dispute the following transaction(s) as unauthorized. I did not make them. I did not authorize anyone to make them on my behalf. I did not receive goods or services for these amounts.

1. Date: [date]
   Amount: $[amount]
   Merchant or payee: [name as shown]
   Reference: [description or ID]

I first noticed these items on [date] while reviewing my statement or online activity. I reported the problem by phone on [date], confirmation [number, if any]. I have blocked the card or changed the login on the affected account.

If this is a credit card, this letter is notice of a billing error under the Fair Credit Billing Act. If this is a debit card, ATM withdrawal, or ACH debit, I am asserting an error under Regulation E, 12 CFR Part 1005, including an unauthorized electronic fund transfer.

Please investigate these items and send written findings. Credit my account for any unauthorized amount, plus related fees or interest. For a Regulation E claim, if you cannot finish in the time the rule allows, apply any provisional credit the rule requires.

Please confirm that you received this dispute. Contact me at the phone or email above.

Sincerely,
[Your name]
[Last four digits only]

Enclosures: marked statement or screenshot; timeline; police or identity-theft report if I filed one.

Don't mail a credit card dispute to the payment address on the return coupon. Use the billing-inquiries address on the statement. That mix-up still happens all the time.

Credit, debit, and ACH follow different rules

One letter can cover several rails if you name the account. The clocks behind it do not match.

Visa, Mastercard, and other networks also advertise zero-liability policies, which are company or network rules and can be more generous than the statute. They do not replace timely notice.

Deadlines that actually bite

Both consumer rules generally count 60 days from when the institution sent the statement, not from the day of the purchase. That window is easy to miss. Miss it, and the bank may have no duty to investigate under those rules.

A lost card or PIN tightens Regulation E liability. Tell the bank within two business days after you learn it was lost or stolen. Your liability for later unauthorized transfers is then the lesser of $50 or the amount sent before notice. Wait past those two business days and the cap can rise to $500. Stay silent more than 60 days after the statement, and later unauthorized transfers can fall on you.

That two-day cap covers a stolen card or PIN. A surprise ACH debit that used your account numbers is a different fact pattern. Report it the day you see it.

To be honest, waiting for a paper statement is how people blow the clock. If the charge is already in your app, start the claim that day. Follow with the letter.

If you have already spent an afternoon on hold, scribbled a confirmation number on a receipt, and then realized you never listed the one charge from a merchant name you do not recognize, you are in a very ordinary mess, and the letter is how you turn that mess into a dated claim instead of a fuzzy memory.

Send it in a way you can prove

Do these in order if you can.

1. Save the statement or export the transaction. Mark each disputed line. Write the date you first saw it.
2. Call or use in-app fraud tools if the card still works. Grab a confirmation number. Then send the letter.
3. Address credit mail to billing inquiries. For checking and debit, use the error address in the deposit agreement or the bank's disputes page.
4. Upload a copy through the bank's secure portal if it time-stamps the file. Screenshot the confirmation.
5. If you use U.S. Mail, keep tracking. Store the receipt with your copy of the letter.
6. Pay the part of the bill you are not disputing. Credit accounts can still levy late fees on the rest.
7. Set a reminder: 10 business days for many debit and ACH investigations, and the next statement cycle for credit.

Electronic notice can count when the bank accepts it. A portal timestamp beats a note you typed to a generic inbox.

Evidence without the drama

Investigators look at merchant data, device details, and whether someone in the house could have used the card. Specifics help. Rants do not.

You don't need a police report for a routine dispute. File one for identity theft or a large loss if that is what happened, and put the report number in the letter.

Bring the marked statement, a short timeline of when you had the card, when you noticed the charge, and when you called, plus anything showing you did not set up that payee. Skip theories about who stole it.

Turns out, "I don't recognize some charges" is the phrase that slows a file down. List each date, amount, and merchant.

Don't demand a 10-day provisional credit on a credit card. That 10-day piece is a Regulation E concept for many electronic transfers, not an FCBA billing-error rule.

Ugly charges that still may not be unauthorized

A transfer you approved is often outside Regulation E's unauthorized-transfer definition, even when a scammer pushed you to hit send. Fake invoice calls and fake refund scripts land here a lot.

Tell the bank anyway and ask them to look under their fraud policy. Don't rest the whole letter on a right that may not exist for a payment you authorized.

Duplicate charges, wrong amounts, and goods you never got can be credit card billing errors even if you did use the card. Say that plainly if it is a billing problem, not stolen-card fraud.

Person-to-person apps are messy. Some debit-funded payments can fall under Regulation E, and many send-it-yourself cases do not, so name the app, the date, and whether you pressed send.

When the bank says no

Read the denial letter. It should give a reason. Ask for the written findings if they skipped that.

For debit and ACH, the bank should apply the consumer liability rules before it puts the loss on you. For credit, confirm your notice reached the billing-error address inside 60 days of the statement.

If the bank is FDIC-insured and the handling still looks wrong, the FDIC consumer complaint process is built for that, after you have given the bank a chance to answer. The CFPB takes complaints on banks and card issuers too. Have dates, the letter, and the denial ready.

A lawyer can make sense when the sum is large or the file was ignored. That's optional, and it costs real money. Start with the paper trail you already have.

Fill the placeholders today if the charge is still inside the 60-day statement window. Save a PDF of the letter, the attachments, and the portal or mail receipt so you're not rebuilding this from memory next month.