Step 1: Tap on the App Store icon on your home screen
Step 2: Tap on your Apple ID in the App Store application
Step 3: Tap "View Apple ID"
Step 4: Tap on "Payment Information"
Once you have tapped on "Payment Information" you will be brought to a page where you will be able to make changes to your billing information for the App Store.
The instructions above are only for users that have purchaed their subscription from the App Store.
If you have made your purchase directly from SurfEasy please update your billing information from accounts.surfeasy.com/profile