An insurer's written decision gives you the starting point for a complaint or appeal. Use the denial letter, delayed-payment notice, or reduced-loss calculation to identify what the insurer says is wrong. Then match each disputed point with the policy or plan language and the document that supports your position.

If the insurer says the service or loss isn't covered, quote the relevant provision. If it says information is missing, provide the record it identifies. If it values the loss too low, challenge the calculation, line items, or valuation method. File a formal appeal by the written deadline even if you also complain about delay or poor handling.

The process below is for U.S. consumers. Health insurance appeals may have federal protections for eligible plans. Auto and property disputes depend mainly on the policy, state law, and the insurer's claims procedure.

Appeal or complaint: Which route applies?

These routes can overlap, but they don't do the same job:

Route What it does What controls it
Internal appeal Asks the insurer or plan administrator to reconsider a denial, reduced payment, or coverage decision The denial notice, policy or plan documents, and applicable law
Complaint to the insurer Reports delay, poor communication, inconsistent handling, or another unresolved service problem The carrier's complaint procedure and the policy
External review Sends an eligible health insurance decision to an independent reviewer The plan type, state process, or federal external-review rules
State regulator complaint Asks a state insurance department to examine possible claims-handling or compliance problems State agency rules and the regulator's authority

A regulator complaint usually doesn't replace a formal appeal. Send the required appeal before its deadline, even if the regulator is reviewing the same matter. Contacting a regulator also shouldn't be assumed to pause an appeal, lawsuit, limitation period, or policy deadline.

Match the evidence to the denial reason

Organize the file around the insurer's stated reason, rather than sending every document you have.

Insurer's stated reason Evidence that may help
The loss or service isn't covered Declarations page, certificate, summary of benefits, policy wording, endorsements, definitions, and exclusions
Medical treatment isn't necessary or is experimental Relevant medical records, treatment history, provider letter, clinical rationale, and the plan criteria cited in the denial
Information is missing or inconsistent Corrected claim, itemized bill, authorization request, referral, correspondence, and a clear explanation of the correction
The damage or loss is worth less Dated photographs, videos, inventory, repair estimates, invoices, receipts, valuation evidence, and an independent appraisal when the policy allows one
You weren't responsible for the accident Police or incident report, witness statements, dashcam or security footage, photographs, diagrams, and relevant communications
The claim was delayed or mishandled Chronological call log, emails, letters, promised response dates, requests for documents, and proof of when you supplied them
The policy wasn't active or a payment is disputed Premium records, confirmation numbers, cancellation notices, and the policy documents in effect on the incident date

Number the attachments and refer to those numbers in the letter. An unindexed file makes it harder for an adjuster or reviewer to find the answer to a specific denial reason.

Build the file before writing

Read the written decision

Keep the complete denial letter, explanation of benefits, claim decision, adjuster's estimate, or explanation for a delayed payment. Check for:

A phone explanation isn't enough when the written notice says something different. Ask the insurer to clarify the reason in writing and keep the response.

Gather the policy or plan documents

Collect the full policy, declarations page, endorsements, certificate, summary plan description, or health plan evidence of coverage. Mark the definitions, conditions, exclusions, and valuation provisions that relate to the dispute. A general statement that the insurer "usually covers" something doesn't override the written contract.

For health plans, the CMS overview of external appeals describes Affordable Care Act external-review protections. Those protections generally concern non-grandfathered plans, including plans first sold or significantly changed after March 23, 2010. The notice from your plan should identify the external-review process that applies.

Prove what happened

Use complete, relevant records rather than a single page that might be misleading out of context:

A useful witness statement identifies the person's name and contact information, the date and location, the conditions, and the specific observations. "I did not hear a turn signal" is more precise than "The driver was careless." Ask the witness to sign and date the statement, but don't coach or exaggerate it.

Put the dates in one place

Make a one-page timeline showing the incident, claim submission, inspection, document requests, calls, promised response dates, and denial. For each call, note the date, time, representative's name and title, and what was said.

Healthcare.gov's internal appeal guidance advises consumers to keep original documents, submit copies, and record conversation details. Those habits also help with auto and property claims.

File the internal appeal

1. Confirm the deadline and recipient

There isn't one universal U.S. appeal deadline. Use the date and instructions in the denial notice together with the policy or plan documents. The deadline for submitting an original claim is a different deadline from the one for appealing a denial.

Employer-sponsored health plans and state-regulated policies can use different procedures. If the written deadline is unclear, ask the insurer or plan administrator in writing, then submit as soon as possible. Don't substitute a customer-service representative's estimate for the written instructions.

2. Request the material behind the decision

Ask for the information needed to answer the denial, such as:

You may not receive every internal document. A specific written request still creates a record and may show exactly what the appeal needs to address.

3. Make an evidence index

A short index can keep the reviewer from searching through the packet:

  1. Denial letter dated [date]
  2. Policy page [number] and endorsement [number]
  3. Provider or expert letter dated [date]
  4. Records covering [date range]
  5. Itemized bill and corrected claim
  6. Timeline and communication log
  7. Proof of delivery

Use file names that match the index. Keep the originals and an identical copy of everything you submit.

4. Write to each denial reason

Include:

A point-by-point paragraph can be as simple as:

The denial states that [reason]. Section [number] of the policy says [relevant wording]. Attachment [number] shows [specific fact]. I request that the insurer reverse the denial and [pay or authorize the stated benefit].

"That's unfair" may describe how the decision feels, but it doesn't answer the coverage question. Connect each fact to a policy term, clinical criterion, calculation, or disputed event.

5. Use the required submission method

Send the appeal through the portal, to the address, or by the fax number or email listed in the notice. Save the upload confirmation, fax report, delivery tracking, or automatic acknowledgment. If you discuss the appeal by phone, follow up with a written summary.

For an urgent health issue, ask whether an expedited appeal is available rather than waiting for a standard review. Healthcare.gov says a final decision must be made as quickly as the medical condition requires and, in the applicable process, no later than four business days after the request is received. An expedited decision may be delivered verbally, but it must be followed by written notice within 48 hours.

6. Track the response

Calendar the expected response date. If it passes, follow up in writing and keep the follow-up with the original packet. When the insurer requests more information, send the relevant documents and explain which request each one answers.

Health insurance: address the clinical or administrative reason

Health appeals often turn on the denial code or clinical rationale, not just the size of the bill.

If the plan upholds the denial, read the notice for an external-review route. In some cases, a consumer may request an internal appeal and external review at the same time. The Healthcare.gov external review page explains that the available process depends on the issuer and state.

Healthcare.gov says that, when a fee applies, it can't be more than $25 per external review. Under the HHS-administered federal process, decisions made by MAXIMUS are final within that process, with no further review available through that route. Confirm that you have the right process and the correct submission instructions before sending the request.

Auto insurance: prove responsibility and damage value

An auto dispute usually has two separate questions: who was responsible and how much the covered loss costs.

For responsibility, provide the accident report, photographs of vehicle positions and road conditions, dashcam or security footage, witness statements, and a diagram if it makes the sequence clearer. Submit the original video file when possible, along with its date, time, device, and any edits made. Keep an unedited copy.

For the amount of the claim, attach the adjuster's estimate, competing repair estimates, parts and labor details, invoices, towing and storage charges, and evidence supporting the vehicle's pre-loss value. Check the policy's valuation method before relying on comparable vehicles or an independent estimate.

Ask whether the insurer wants to inspect the vehicle before non-emergency repairs. Take reasonable steps to prevent further damage, keep receipts for necessary temporary work, and photograph damaged parts before disposal or replacement.

Property insurance: separate coverage from valuation

A property claim can fail for two different reasons. The evidence may show the repair cost but not the covered cause of loss, or it may show that property was damaged without proving the value of the items.

Collect:

Prevent additional damage when reasonably possible, but ask the insurer how it wants the property preserved for inspection. If the policy provides an appraisal procedure, read the appraisal clause first. Appraisal may resolve the amount of loss without deciding whether the policy covers the event.

Evidence mistakes that weaken an appeal

Mistake Why it hurts Better approach
Sending only bills or repair estimates The documents may prove cost but not coverage or causation Add the relevant policy wording and evidence of what happened
Missing the appeal deadline The insurer may reject the submission as late Use the written deadline and submit before it
Sending original documents You may lose the only copy Submit copies and keep a complete file
Relying on phone calls There may be no reliable record of the conversation Keep a call log and confirm important points in writing
Using vague or exaggerated statements Inconsistencies can damage credibility State what you personally know and identify the source of other facts
Editing photos or videos without preserving originals The insurer may question authenticity Keep the original file and disclose edits made to a working copy
Treating a partial payment as final without checking You may overlook disputed items or release language Review the payment explanation and any release before signing
Assuming a regulator complaint replaces an appeal The complaint may not satisfy the policy's appeal process File the formal appeal separately and on time

When to go beyond the insurer

Follow the next route named in the decision notice after an internal appeal:

A state regulator's authority varies. The agency may examine compliance or handling practices but may not decide every contract dispute, order a particular settlement, or oversee a self-funded employer health plan. Check which agency has jurisdiction before sending a packet.

A denial alone doesn't establish insurance bad faith. The legal standard varies by state and may depend on the policy, investigation, communications, delay, and financial harm. If the claim is high-value, a limitation period may be approaching, or you receive a release or lawsuit papers, consult a licensed attorney in the relevant state.

Order for the appeal packet

Arrange the final packet like this:

  1. Cover letter or appeal form
  2. Denial letter, explanation of benefits, or adjuster's decision
  3. Relevant policy or plan pages with key language marked
  4. Evidence index
  5. Documents arranged by issue or date
  6. Timeline and communication log
  7. Proof of submission

This is general U.S. consumer information, not legal advice. Start with the denial reason and the written deadline. Before sending, verify that the claim number appears on the letter, every listed attachment is included, and the final packet and delivery confirmation are saved in two places.