When executing a credit or debit card payment through the POS and the amount authorized is different than the amount set to the pin pad the cashier has a choice to either accept the amount or cancel the payment. When the payment is cancelled the POS will send another request to the Pin Pad to void the payment. However, if the customer then hits the "Cancel" button the Pin Pad or another error occurs then the payment line is removed on the POS but the void was never successful, which means the charge will remain on the customer's card.