Other Fraud Protection Measures Always verify that the signature belongs to the presenter Do not accept any cards which have not been signed Your terminal should prompt you to enter the last four digits of the account number to verify that the account number on the magnetic stripe is correct or your terminal may display the entire card number for comparison to that on the front of the card. If your terminal does not prompt for this, call the terminal help desk and ask for this feature. They will give you further instructions. This is the single most frequent cause of chargebacks. Fortunately, this is often the easiest to prevent or reverse.
Card issuers are responsible for initiating copy requests.
Usually they are initiated to resolve billing disputes or to comply with a subpoena. Fullfilling copy requests is very important. When requests are not fulfilled or not filled within the prescribed time period, they almost always result in a chargeback. So it is in your best interest to respond quickly to copy requests. If you do receive a legitimate duplicate processing chargeback, do not issue a direct credit to the cardholder - the credit will automatically be applied.