You have two ways to use your Visa Debit Card. You can swipe your card and use your PIN, or you can choose credit and sign for your purchases. Occasionally, high transaction volumes can cause transactions to be declined even if your purchase amount doesn't exceed your available funds. If this happens, ask the merchant to process your transaction again using the opposite method. For example, if you originally tried running the transaction as a credit, ask to run it with your PIN. If you originally used your PIN, ask to run it as a credit transaction.