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

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

To cancel Grok, make sure you use the exact billing channel where you signed up—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