This article explains how you can add or edit your billing information
Step 1
When logging into your Spark Site, select Marketplace and then select 'Update Billing'
Step 2
Once you're in your myaccount area, select 'Add New Credit Card'
Step 3
Enter your new credit card details then select 'Add a new address'
Step 4
After filling out the billing address modal, select 'Save Changes' and when back in the Payment Method window, select 'Save Changes' and you're done!