[BUG] Plan upgrades can cause multiple org uuids for the same email and lead to double billing or denial of service

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When I reached the limits of Pro plan once, I chose to upgrade to Max, and my card was billed at once, When the current term of Pro expired, Pro was billed once more. The AI support suggested to cancel the Pro plan (which means paying Pro and Max for a partial month). One month later, I found myself listed as a free user, so unable to use at least Claude Code.
I contacted support a few times during last 6 days, but nothing but AI responses

Organization IDs:

• Old: 9a3e52da-8210-4a43-9258-7e56053cd4ce
• New: 99fa64fc-54dd-45f1-b60c-80b882a2dbf0

Support references:

• Conversation IDs: 215474477654541, 215474514004990, 215474517631670

Relevant card transaction numbers have been submitted to support

What Should Happen?

No more payments for the Pro plan after the upgrade, Max plan should show up in account details

Error Messages/Logs

Steps to Reproduce

I am currently nit in a position to try reproduce the situation, because it costs money

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.81

Platform

Other

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_