How to Write a Dispute Letter to a Bank: Deadlines, Content, and Delivery

To write a dispute letter to a bank, put the specific transaction, the reason it’s wrong, and the fix you want onto a single page, then send it by certified mail to the address the bank designates for billing inquiries. Done correctly, that letter triggers federal deadlines the bank has to meet. Done sloppily, or sent to the wrong address, it may not trigger anything at all.

Two federal laws decide what your letter can do. The Fair Credit Billing Act covers credit card accounts. The Electronic Fund Transfer Act covers debit cards and checking accounts. The drafting is similar for both. The deadlines and the stakes are not.

Send It Before the Deadline Runs

With a credit card, your card issuer has to acknowledge your written notice within 30 days and resolve the dispute within two billing cycles, never more than 90 days.¹ You can withhold payment on the disputed amount and related finance charges while the investigation runs.² Federal law caps your liability for unauthorized credit card charges at $50 regardless of when you report, and most major issuers waive even that.

With a debit card, the money is already out of your account, and the reporting clock controls how much you can lose. Report an unauthorized transaction within two business days of learning about a lost or stolen card, and your liability caps at $50. Wait longer than two business days, and liability can rise to $500. Wait more than 60 days from the statement date, and your exposure for transfers after that window becomes unlimited until you notify the bank.³

For debit disputes, you don’t have to start in writing. Oral notice is enough to trigger the bank’s investigation obligations under Regulation E.⁴ But the bank can require written confirmation within 10 business days of your call, and if you don’t send it, the bank doesn’t have to give you provisional credit.⁵ Call first to start the clock, then send the letter.

Gather the Specifics First

A letter built on specifics gets resolved faster than one that reads like a complaint. Before you draft anything, pull together:

The account number, or at least the last four digits tied to the disputed transaction.
The exact date, dollar amount, and merchant name as they appear on your statement. Banks process thousands of disputes; precise details keep yours from being misrouted.
Receipts, order confirmations, or cancellation emails showing what you actually agreed to.
Any correspondence with the merchant. For credit card disputes over the quality of goods or services, federal law expects you to have tried to resolve the problem with the seller first.²
A police report number if the charge involves fraud or identity theft.

Make copies of every document before you send anything. Originals sent to the bank are not reliably returned.

What to Put in the Letter

The letter doesn’t need to be long, and it shouldn’t argue the law. Banks want clear facts, not briefs.

Open with a header listing your full name, mailing address, phone number, and the date. Below that, put the bank’s dispute department and its mailing address. Add a subject line that identifies the dispute at a glance, something like “Dispute of [date] Transaction on Account Ending in [last four digits].”

In the body, state the transaction you’re disputing: date, amount, and merchant name. Then explain in one or two sentences why it’s wrong. Keep it factual. “I was charged $200.00, but the agreed price was $20.00” works better than a paragraph of frustration. If the charge is completely unauthorized, say so plainly: “I did not make or authorize this transaction.”

Say what you want the bank to do. A full reversal of a fraudulent charge. A specific dollar adjustment to correct an overcharge. A provisional credit while the investigation runs. Close by listing the documents you’ve enclosed. One page is plenty.

If identity theft is involved, include your police report number. If you’ve already contacted the merchant, attach the exchange and say so in the letter.

Send It to the Right Address, the Right Way

This is where disputes quietly fail. For credit card accounts, FCBA protections only apply if the issuer receives your notice at the address it designates for billing inquiries. Not customer service. Not the payment envelope.⁶ The correct address appears on your monthly statement, usually in a section labeled “billing inquiries” or “send billing error notices to.” A letter sent to any other address lets the bank argue it never received proper notice.

Send the letter by USPS Certified Mail with Return Receipt Requested. The receipt is your proof that the bank got your dispute within the legal deadline. As of January 2026, Certified Mail is $5.30 and the return receipt adds $4.40, for $9.70 before postage.⁷ An electronic return receipt is $2.82 if you don’t need the physical green card.

Many banks also accept disputes through online banking portals that generate a confirmation number and timestamp. That counts as proof of timely submission. Use whichever route you prefer, but keep a complete copy of the letter and every attachment.

What the Bank Has to Do Next

For a credit card dispute, the issuer must acknowledge your letter in writing within 30 days unless it resolves the matter sooner, and it must finish investigating within two billing cycles (90 days maximum).¹ If it finds an error, it corrects the account and refunds related finance charges. If it disagrees, it owes you a written explanation and must provide supporting documents on request. During the investigation, the issuer cannot report the disputed amount as delinquent or send it to collections.⁸ You still need to pay the undisputed portion of your bill on time.

For a debit card or checking account dispute, the bank has 10 business days after receiving your notice to investigate and report its findings. If it needs more time, it must provisionally credit your account for the disputed amount within those 10 business days and complete the investigation within 45 calendar days.⁵ The provisional credit is required when the bank extends the timeline, not optional.⁹ Accounts open less than 30 days get 20 business days for the initial investigation instead of 10, and the extended window stretches to 90 calendar days for point-of-sale debit transactions and foreign-initiated transfers.⁴

If the bank confirms an error on a debit dispute, it must correct your account within one business day and refund any fees it charged as a result, including overdraft fees triggered by the disputed transaction.¹⁰

If the Bank Denies the Dispute

A denial letter has to explain the bank’s reasoning and tell you that you can request copies of the documents it relied on.⁹ Request them. The evidence behind a denial is sometimes thinner than the denial letter suggests.

If the bank issued provisional credit during the investigation and then denied the dispute, it can reverse the credit, but it must give you five business days’ notice before pulling the funds and must honor checks and automatic payments during that window without charging overdraft fees.⁴

You can file a complaint with the Consumer Financial Protection Bureau, which forwards your dispute to the bank for a response and publishes complaint data publicly.¹¹ It won’t force a reversal, but banks tend to look harder at a dispute that arrives with a federal regulator attached to it.

1
Office of the Law Revision Counsel. 15 USC 1666 – Correction of Billing Errors
2
Federal Trade Commission. Using Credit Cards and Disputing Charges
3
eCFR. 12 CFR 205.6 – Liability of Consumer for Unauthorized Transfers
4
Consumer Financial Protection Bureau. 12 CFR 1005.11 – Procedures for Resolving Errors
5
GovInfo. 15 USC 1693f – Error Resolution
6
eCFR. 12 CFR 1026.13 – Billing Error Resolution
7
USPS. USPS Price List – Notice 123
8
Federal Trade Commission. Fair Credit Billing Act
9
National Credit Union Administration. Electronic Fund Transfer Act (Regulation E) – Section: Procedures for Resolving Errors
10
eCFR. 12 CFR Part 1005 – Electronic Fund Transfers (Regulation E)
11
Consumer Financial Protection Bureau. Submit a Complaint