My CNF stack failed with an "Internal Failure" and now I can't rollback or update it!

UPDATE: I opened an AWS support ticket for this problem and it's apparently an internal issue that can only be resolved by the CloudFormation team.

So, I tried to import existing resources into my CloudFormation stack and the process failed. It looks like it might have timed out or something, but the latest message was "IMPORT_ROLLBACK_FAILED" due to an "Internal Failure". Now my stack is stuck and I can't change it at all. There is no "continue rollback" option or "update" option. The only thing I can do is delete the stack, which is something I do not want to do. I can't even ask AWS Support about it because we only have the "Basic" support plan on this account and that only covers billing questions and quota increases.

What options do I have? Pay more to unwedge CFN? That should be AWS's problem, not mine!

Anyway, here's what I see in CFN console. Does anyone have any thoughts on how to fix this?

2022-12-04 02:18:52 UTC-0500  datastore-sg  IMPORT_ROLLBACK_FAILED  Internal Failure
2022-12-04 02:18:51 UTC-0500  rdssngSG  UPDATE_FAILED The security token included in the request is invalid
2022-12-04 02:18:50 UTC-0500  rdssngSG  UPDATE_IN_PROGRESS  Remove stack-level tags from imported resource if applicable.
2022-12-04 02:18:38 UTC-0500  datastore-sg  IMPORT_ROLLBACK_IN_PROGRESS The security token included in the request is invalid
2022-12-04 02:16:45 UTC-0500  rdsSG UPDATE_FAILED The security token included in the request is invalid
2022-12-03 04:32:59 UTC-0500  rdsSG UPDATE_IN_PROGRESS  Apply stack-level tags to imported resource if applicable.
2022-12-03 04:32:58 UTC-0500  rdsSG IMPORT_COMPLETE Resource import completed.