How quickly should I report an unrecognised charge?

As soon as you see it. Protections for unauthorised transactions generally depend on prompt reporting, and some schemes set hard time limits measured from the statement date.

Is it safe to put my account number in a letter?

Use the last four digits, or the account number for a current account. Never send a full card number and never send the security code. No bank needs either to investigate.

What is the difference between a dispute and a chargeback?

A dispute is you telling the bank something is wrong. A chargeback is the mechanism the bank may use to claw the money back from the merchant's bank. You raise the first; the bank decides on the second.

Should I cancel the card?

If the charge was unauthorised, yes, and say so in the letter. If it is a billing dispute with a merchant you do know, cancelling the card does not cancel the underlying agreement.

What if the bank rejects my dispute?

Ask for the decision and the reason in writing, then take it to the relevant ombudsman or regulator. The written record is what makes that possible.

Change letter type

Bank transaction dispute letter

There is a charge on your account you did not make or recognise.

Banks work from reference numbers and dates. A dispute that names the exact transaction, the amount and the date gets investigated; one that describes a strange charge last month does not.

Report it as soon as you notice. Most protections depend on you raising it promptly, and some have hard deadlines.

Tone

Firm is still professional. It states a date and what happens after it, rather than raising its voice.

About you

Your full name

Your address (optional)

Account number or last four digits

Never send full card numbers by email. The last four digits are enough to identify it.

Your bank's address

Named person, if you have one (optional)

The transaction

Name on the transaction

Amount

Date it was taken

Transaction reference (optional)

What is wrong with it

Anything else that matters (optional)

When you cancelled, where your card was, whether you still hold it.

The card itself (optional)

What you want

Days you are giving them (optional)

What you will do if unresolved (optional)

Only used in the firm version.

Date format

Your letter is never uploaded, because it's built in your browser. Nothing you type here is saved, so refreshing starts again.

24 August 2026

Disputed transaction of on

Dear Sir or Madam,

A charge of to was taken from my account on. I am disputing it because.

Please look into it and let me know what you find. I am happy to provide anything that helps the investigation.

Yours faithfully,

Account

Still to fill in: your full name, account number or last four digits, your bank's address, name on the transaction, amount, date it was taken, what is wrong with it.

A finished example

The same template with every field filled in. The names and details are invented.

Ines Duarte

Rua do Alecrim 44

1200-018 Lisbon

Portugal

Disputes Department

Banco Atlântico

Av. da Liberdade 210, Lisbon

24 August 2026

Disputed transaction of EUR 89.99 on 3 August 2026

Dear Sir or Madam,

A charge of EUR 89.99 to NORDSTAR DIGITAL LTD was taken from my account on 3 August 2026, reference TX-99401882. I am disputing it because I cancelled this subscription before the charge was taken.

I cancelled this subscription on 11 May and received an email confirming the cancellation, which I have kept. No service has been provided since that date. The card has not left my possession.

Please look into it and let me know what you find. If you could come back to me by 8 September 2026 I would be grateful. I am happy to provide anything that helps the investigation.

Yours faithfully,

Ines Duarte

Account ending 8842

Disputed transaction of EUR 89.99 on 3 August 2026 Dear Sir or Madam, A charge of EUR 89.99 to NORDSTAR DIGITAL LTD was taken from my account on 3 August 2026, reference TX-99401882. I am disputing it because I cancelled this subscription before the charge was taken. I cancelled this subscription on 11 May and received an email confirming the cancellation, which I have kept. No service has been provided since that date. The card has not left my possession. Please look into it and let me know what you find. If you could come back to me by 8 September 2026 I would be grateful. I am happy to provide anything that helps the investigation. Yours faithfully, Ines Duarte Account ending 8842

Questions

How quickly should I report an unrecognised charge?: As soon as you see it. Protections for unauthorised transactions generally depend on prompt reporting, and some schemes set hard time limits measured from the statement date.
Is it safe to put my account number in a letter?: Use the last four digits, or the account number for a current account. Never send a full card number and never send the security code. No bank needs either to investigate.
What is the difference between a dispute and a chargeback?: A dispute is you telling the bank something is wrong. A chargeback is the mechanism the bank may use to claw the money back from the merchant's bank. You raise the first; the bank decides on the second.
Should I cancel the card?: If the charge was unauthorised, yes, and say so in the letter. If it is a billing dispute with a merchant you do know, cancelling the card does not cancel the underlying agreement.
What if the bank rejects my dispute?: Ask for the decision and the reason in writing, then take it to the relevant ombudsman or regulator. The written record is what makes that possible.