[BUG] [Billing] Max 5x → Max 20x upgrade fails — same canceled PaymentIntent reused on every attempt (void_invoice)

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?

Cannot upgrade from Max 5x to Max 20x on claude.ai. Every payment attempt fails with the same Stripe error referencing a canceled PaymentIntent. The Anthropic backend reuses the same dead PaymentIntent ID on every retry instead of generating a new one.

Account email: hello@ismaildasci.com
Organization UUID: c6262a29-bb07-472f-b02e-2443589125b8
Rate limit tier: default_claude_max_5x
Billing type: stripe_subscription

PaymentIntent ID: pi_3TbP0jBjIQrRQnux0LgiMJ4D
Status: canceled
Cancellation reason: void_invoice
Created → Canceled: ~69 seconds
Bank confirms: no transaction received

Stripe error code: payment_intent_unexpected_state
Error message: "This PaymentIntent's mandate_data could not be updated because it has a status of canceled."

Tried (all failed with the SAME canceled PI):

• Multiple cards (regular + virtual)
• PayPal
• Stripe Link + manual card entry
• Chrome, incognito, mobile browser
• iPhone app (says "purchased on another platform")
• Cache/cookie/localStorage clear
• Pro downgrade attempt

Fin AI bot loops with generic troubleshooting, cannot escalate to human despite multiple explicit requests. Contact Sales form — no response. Sent emails to support@, usersafety@, sales@ — auto-replies only.

Related issues: #55982, #55266, #56281, #54204, #59027, #50710, #45890

What Should Happen?

A new PaymentIntent should be generated for each upgrade attempt. The stuck subscription state on the Anthropic backend should be reset so the Max 5x → Max 20x upgrade can complete successfully.

Error Messages/Logs

Steps to Reproduce

1. Active Max 5x subscription on claude.ai
2. Settings → Billing → Upgrade to Max 20x
3. Enter card details
4. Submit payment
5. Fails with payment_intent_unexpected_state error referencing same canceled PI on every attempt

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

N/A — this is a claude.ai web billing issue, not a Claude Code CLI issue. Reporting here as it appears to be the most monitored Anthropic repository (per #55982, #50710, #56281).

Platform

Other

Operating System

Other

Terminal/Shell

Other

Additional Information

_No response_