If your credit card has expired and you need to update it, or you want to pay with a different credit card, you can do it from your "control panel" Click the "Dashboard" link located on the top menu, then click "Payment Method" from the left menu.
If you are using PayPal to pay for your subscription, you need to update your payment information directly on your PayPal account.

However; if you don’t have a PayPal account, but you used PayPal check out without a credit card you would need to cancel your current Pinmaps.net subscription and start a new one with the new credit card.
Rest assured you won’t lose your map and pins when you cancel your subscription to start a new one with the updated payment information.