To cancel Grok, be sure to stop your subscription through the same billing...

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

To cancel Grok, be sure to stop your subscription through the same billing channel you originally used—whether that’s grok.com via Stripe, Apple Subscriptions, Google Play, X Premium on x.com, or console.x.ai for Business/API