Unable to upgrade to Pay as you go from Free Tier

Summary:

I have a Free Tier that I want to upgrade to a Pay as you go account .

However when I visit the upgrade page following steps mentioned it is stuck in loading and shows error. I have attached screenshot of the error. The console shows below error message as well

Content (required):

The error message available on the console indicates an issue on the server side. Please help to activate the same.

{
  "code" : "404 NOT_FOUND",
  "message" : "Plan with subscriptionId: 7986750 was not found by SPM."
}'

I would like to do the upgrade before Tuesday when my instances would be automatically shut down because OCI tags them as idle. I have production traffic being served from them.