If you'd like to update your current payment method, there are two ways:

1. Pay your next installment with a new payment method.

2. Change your payment method in payment settings:

Choose "Profile" from the main menu and "Payment Settings" on the left-hand side.

Here, the top payment method is your current default payment method.

You can switch the default payment method by choosing between existing payment methods (or remove an old payment method):

Or, you can add a new payment method if you wish (any credit/debit card or a US checking account):