Do I have to dispute a credit card charge in writing?

To get the protections of the Fair Credit Billing Act, yes. The law covers a written notice sent to the address the issuer gives for billing inquiries. Calling or using the app often works, but it does not by itself trigger the issuer's legal duties to acknowledge and investigate.

The issuer must receive your letter within 60 days after it sent the first statement that shows the error. Mail it early. The deadline is counted from the statement, not from the day you noticed the charge.

What does the issuer have to do after it gets the letter?

Acknowledge the dispute in writing within 30 days, unless it has already fixed the problem, and resolve it within two billing cycles and no more than 90 days. While it investigates, it cannot try to collect the disputed amount or report it as late.

Do I have to pay the disputed charge in the meantime?

You can hold back the disputed amount and any interest on it while the investigation is open. You still have to pay the rest of the bill on time.

Does this work for debit cards or loans?

No. The Fair Credit Billing Act covers credit cards and other revolving credit accounts. Debit card and bank transfer errors fall under a different law with its own deadlines, and installment loans are not covered.

How much does it cost?

For a one-page letter from a prepaid balance: $8.61 certified, $11.64 with an electronic return receipt, or $14.27 with the green-card return receipt. Paying for just that letter by card costs $8.83, $11.83 or $14.42.

How to dispute a credit card billing error by certified mail, with AI

A charge you never made, a charge for the wrong amount, something you returned or never received, a payment the issuer didn't credit: federal law gives you a way to force your credit card issuer to investigate. The Fair Credit Billing Act protects you when you dispute the error in writing, sent to the issuer's billing inquiries address, and received within 60 days of the statement that first showed it.

That makes two things matter: a letter, and proof of the date it arrived. With Mailsnail connected to your AI assistant, you can draft and mail it by certified mail in one conversation, without a printer or a trip to the post office.

Connect once

Add this URL to Claude, ChatGPT, Cursor or any app that supports MCP connectors, then sign in:

https://api.mailsnail.dev/mcp

Step-by-step instructions for each app are on the setup page.

Find the right address first

Your statement lists an address for billing inquiries or billing errors. It is usually not the address where payments go, and a dispute sent with your payment does not count. Check the back of a paper statement or the last page of the PDF. If you can't find it, ask the issuer for its billing error address.

Draft it with the assistant

Give it the facts plainly. For example:

My Visa statement dated October 20 shows a charge of $412.80 from "Harbor Appliance" on October 3. I ordered a dishwasher from them and cancelled the order the same day, and it was never delivered. Draft a billing error dispute letter under the Fair Credit Billing Act to First Example Bank, Billing Inquiries, PO Box 1234, Wilmington DE 19850. My name is Dana Reyes, 77 Alder Lane, Columbus OH 43215, and the account ends in 4821. Ask them to remove the charge and any interest on it. Then send it by certified mail with an electronic return receipt. Show me the proof first.

A billing error letter needs only a few things:

Your name and address, and your account number. The last four digits are enough if you'd rather not mail the full number.
The charge you are disputing: merchant, date and dollar amount.
Why you believe it is an error, in a sentence or two.
What you want: the charge removed, the amount corrected, or the payment credited.

Keep it short and factual. Describe copies of receipts, order cancellations or return confirmations in the letter, and keep the originals. Never mail originals.

What happens next

verify_address checks that the issuer's address is deliverable. Free.
preview_letter renders the letter and returns a proof PDF and the exact price. Nothing is charged.
You read the proof. Check the address against your statement and the amount against the charge.
send_letter mails it by certified mail with the return receipt you chose and gives you a receipt token.

Pick your proof

Service	What you get	From a balance	One letter by card
Certified	USPS tracking and proof of mailing	$8.61	$8.83
Certified + electronic return receipt	The recipient's signature as a PDF	$11.64	$11.83
Certified + green card	The signed card mailed back to you	$14.27	$14.42

One page, black and white. Extra pages are priced at our cost and the preview always shows the exact figure.

Know the clock

Who	Deadline
You	Letter received within 60 days after the first statement with the error was sent
Issuer	Written acknowledgement within 30 days of receiving it
Issuer	Resolution within two billing cycles, and no more than 90 days

While the dispute is open, the issuer can't collect the disputed amount, charge you interest on it if you turn out to be right, or report it as delinquent. Pay the undisputed part of your bill as usual.

Keep the record

Save the receipt token. Later, ask the assistant "did the bank get my dispute letter?" and get_letter returns the USPS tracking number, the latest scan and, for an electronic return receipt, a link to the signature PDF. Keep the statement, the letter and that delivery record together. If the issuer misses its deadlines or rejects the dispute without explanation, that file is what you attach to a complaint to the Consumer Financial Protection Bureau.

What Mailsnail doesn't do

We print and mail exactly what you approve. We don't give legal advice or decide whether a charge qualifies as a billing error. If a lot of money is at stake, or the issuer ignores the letter, talk to a consumer attorney or file a complaint with the Consumer Financial Protection Bureau.