To cancel Grok, be sure to use the same billing channel you signed up...

https://wiki-book.win/index.php/Cancel_SuperGrok_on_Android_-_What_Menu_in_Google_Play%3F

To cancel Grok, be sure to use the same billing channel you signed up with—whether that's grok.com/Stripe, Apple Subscriptions, Google Play, X Premium on x.com, console.x.ai for Business, or console.x.ai Billing for API auto-recharge