Welcome to the Community, @david-sawyer, and good morning! Based on your post, it sounds like you have payments set up in your account but are encountering an error when processing a credit card. Let's start with some basic browser troubleshooting so we can eliminate that as a factor.
We can start with those steps and see if that fixes what you are experiencing. If you try those steps and still have the same problem, it may be related to a known issue, so please reach out to me through this post and we can continue troubleshooting.
Looking forward to hearing from you!