To cancel Grok, make sure you use the exact billing channel you originally...

https://bizzmarkblog.com/how-do-i-request-an-apple-refund-for-supergrok/

To cancel Grok, make sure you use the exact billing channel you originally signed up with—whether that’s grok.com/Stripe, Apple Subscriptions, Google Play, X Premium on x.com, or console.x.ai for Business or API billing