You can always check your billing history on the CAMPs page by going to View your transaction history. Then choose a date in the Time period drop-down arrow, and locate the order number to see the order details. You can also print that by hitting the Print this page.
If you still have a hard time changing the payment method, I'd recommend filling up our chat support information by following the steps below. In this way, one of our Customer Care will communicate with you as soon as possible. Due to COVID-19, our support is currently limited to chat only.