Appreciate it. For reference to others reading through here, I and a number of others have been able to re-enter payment info without issue, but Substar is finicky about what banks they can and can't work with, especially outside the US, so unfortunately there is a possibility of further issues with this. Still worth checking and trying though.
For those who find they absolutely, positively cannot get Substar to process their payment anymore, I DO have a Patreon: : Bitshiftgames (can't link in comments due to itch's idiotic anti-spam). Only use that as a last resort though: I won't be doing game discussion over there, as I have to keep it a "clean" tip jar. Can still sub at the same tiers though.