Automatically Notifying Customers Of a Declined Credit Card.
When a customer's credit card is declined do they receive an email?
If your store is configured to authorize credit cards when a customer orders [Settings/Compatible Software (edit)/ Payment Gateways (preferences)/Authorize Credit Cards], the customer will be notified instantly and will have the opportunity to re-enter their information. You can also set a Declined Explanation in Settings/Compatible Software (edit)/ Payment Gateways (preferences)/Declined Explanation.
If your store is not authorizing credit cards in real time and a customer's card is declined, your business should contact that customer in the manner that you feel is best.