Click on the MY ACCOUNT button on the right edge of your screen. Once you're logged in, you'll be taken to your profile. Notice that all of your orders are displayed on this page. Locate the order you need to pay. To the right of the order is a PAY link. Click this link. On the next page, click "Pay with Bank or Credit Card" which will already be ticked. Once you do this, the module will expand and you'll be able to add your updated credit card information. Follow the prompts to complete the process.