How To Update Payment Details
To update your payment method in FastSpring go access this link.
There you will need to fill in the email address on which you've registered your account and the click "Continue".
At that email address you will receive a link which will take you to a page where you can manage your account.
After you access the link click the "Click here to manage your orders" button to which will take you to manage your account.
Once you accessed the account management go to the "Account Details and Payment Methods" menu where you'll find the option "Add Payment Method".
You can choose to apply the new payment method to all your subscriptions.
Fill in your new card details and click "Save Payment Details".
You're all set!