[BUG] Online payment process is broken - cannot pay, cannot cancel

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?

I have been trying all day to upgrade from Pro to Max x5 online here: https://claude.ai/settings/billing

Every attempt yields "Payment attempt failed. Please try again later. ... "

Repeated attempts yield the same result. Billing details have not changed since multiple previous payments. Attempts to update billing details via Update apparently succeed but do not seem to persist.

The payment method is not the problem; different browsers and payment methods make no difference, nor does clearing cookies. Bank confirms the payment attempt is not reaching them.

Even more seriously:

Attempting to Cancel subscription apparently succeeds - yet visiting the billing page again hours later, I am still told 'Your subscription will renew on...'.

Again, repeated attempts yield the same result - it is impossible to cancel.

Fin AI Agent promises (after much cajoling) that a human will contact me; this does not happen.

What Should Happen?

It should be possible to (i) upgrade and (ii) cancel a Claude subscription via https://claude.ai/settings/billing

Error Messages/Logs

On attempting to upgrade: "Payment failed. Please try again later. If the problem persists, contact support at https://support.anthropic.com/"

On cancelling: no error; cancellation appears to succeed, but does not actually succeed.

Steps to Reproduce

On a Pro subscription, go to https://claude.ai/settings/billing

Attempt to (i) upgrade to Max 5x or (ii) cancel.

Consistently reproducible for me.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.133

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_