There are a number of reasons why your payment may have been declined. For example, you made a mistake when you were entering your payment details, there were insufficient funds on your card, or there is an issue with your card. If your payment was declined, you could try again using a different card.
If you are unable to determine the reason your payment was declined or the problem persists, the best course of action is to contact your bank for more information.
Moreover, it is not mandatory to pay for your booking with the same credit card that you bring with you when you pick up the car.