Thank you very much for following up with that!
Since this discussion will be here for a long time, and others may find it by searching, I want to clarify what was likely happening. You initially said your problem was with Apple Pay, which is a slightly different feature than what was broken.
It sounds like your issue was with a balance on your online Apple Account, used for purchases at the Apple Online Store and Mac and iPhone App store(s) and Apple Music, among others. That account got frozen because of problems/changes with your payment method. In this case, that left an outstanding balance.
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The resolution seems to be the same -- add a 'new' payment method (even if the same as the old payment method) and if the 'new' payment method works now, you are good to go. If the new one is similar enough to the old 'broken' payment method, the system will likely remove the broken one in the process -- so no 'updating' of a broken payment method is needed.