When an order is placed, the transaction is first sent to the bank. The bank checks to see if the account has the necessary funds to complete the order. If the funds are present, the bank will remove them from the account and set them aside "pending" until the transaction is complete.
The transaction is then sent to the payment system. The payment system is responsible for checking if the credit card information inputted matches what the bank has on record. If the information does not match, the transaction will fail the check. If failed, the order is considered declined and a new order will need to be placed. After time, the bank system will return the "pending" back to the account automatically. This process can take between 5-20 business days depending on the type of bank.