Here is how easy it is to update your credit card details:
Click on your profile icon located at the top left corner of your screen. A dropdown box will appear, go ahead and click account.
Select "Billing" and click "Open Billing Portal"
Click "Open"
Next click "Add Payment Method" and update your credit card details and follow the payment prompts. Ensure that your new payment method is set at "Default"
You are all set!