Steps
Sign into your Online Account Portal by visiting Relaygo.com/families and clicking on the "Account" link. Use your existing Relay account credentials to login to your account
Click Payment in the drop down menu
If you need to add a new form of payment, scroll down to the Payment Information section
Enter your new payment information, then click Update payment
All Done!
Additional Notes
Only account owners can update payment information on an account
If updating your billing address, you'll need to re-enter your credit card information as well