Hi there, Critchelow. Thanks for joining this thread.
I would like to ask a few questions about your concern. Have you tried following the steps provided by my colleague above? If yes, normally, you should be able to see the Edit option in the Billing Information section once you log in to Customer Account Management Portal Site (CAMPS).
Are there payments already associated with your account? If yes, In QuickBooks Desktop, editing the payment method can be done by following the steps below. Let's try them one more time and see if you'll be getting the same message you had.
If the same things happen, I would recommend contacting our specialists to investigate why it's happening on your end. To make sure we address your concern on time, please check out their work schedule in this link: Support hours and types. Go to the QuickBooks Desktop section to view details.
Let me know how everything goes. I want to ensure that you're good to go. Take care!