Can someone explain what happens when a credit card payment is declined?
the order status is set to Declined ('D') and the response from the processor is capture in the order. Results are shown in the far right of the order detail view in the admin.
What the customer sees varies widely from version to version. I believe in the current version they just get a message that it was declined and (I believe) the option to go back to the checkout process and change info and submit again. I don't think the response from the provider is visible to the customer, but I could be wrong.