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I gave out my card details or a code: what to do

In short

Call your bank immediately, on the number on the back of your card or in the official app, and block your card. Do it even if no money has been taken yet: a card number or code that has been handed over is used to pay or approve a transaction within minutes. Then write down what happened and file a police report.

Why this works

A card number or verification code is only worth something to the scammer while it works. Blocking the card makes it useless, and it is the only step whose effectiveness depends on how fast you are. The number you call matters as much as the speed: the one your caller gave you, or the one that showed during the call, can lead back to the same person. A bank never asks you to move money to protect it, and no service ever asks you to give it a verification code — if you were asked for one, the transaction under way is the scammer's.

Step by step

  1. Hang up, then call the bank yourself

    If the exchange is still going on, end it. Then dial the number on the back of your card or use the official app. Wait a few minutes or use another line: a line can stay open if you don't hang up properly.

  2. Block the card and report the transaction

    Ask for the card to be blocked and report any transaction you didn't make or that you approved under pressure. Don't approve any further notification or code until the bank has confirmed the situation is under control.

  3. Write down the details while they are fresh

    Time of the call, number displayed, name given by the caller, amounts mentioned, messages received. Don't delete anything: these are the elements of your police report and your dispute.

  4. File a report, report it, secure the rest

    File a police report, then report what happened to Cybermalveillance.gouv.fr (in France). If you also gave out a login or a password, change it from a clean device and sign out the account's active sessions.

The most common mistakes

  • Calling back the number that was displayed, or the one given during the call.
  • Waiting to see a charge before reacting: blocking the card is meant to prevent it.
  • Approving “to cancel” a notification or code that arrives just after the call.
  • Believing a caller who knew your details must have been genuine: those details often come from a data breach.
  • Not filing a report out of embarrassment: it is also the basis for your dealings with the bank.

A tool to do it

The attacks this defeats

Official sources

Other guides · Last updated: 2026-10-07.