I've gotten the same error today after attempting (again - days later) to add back my credit card. So far the only solution I've found is to buy crysta and pay for a sub that way until they resolve these issues. I created a ticket for it a while back. The response was that most likely it was an issue with my bank or my card (on my end). But all is in good standing and others are having the issue so it's clearly on their end.

Anyway, I replied that my card(s) are in good standing, and asked how to resolve it. They auto-closed my ticket and said that if I had any other issues I could submit a new ticket...yeah nah not gonna waste my time again.