To cancel Grok, make sure you use the exact billing channel where you signed...
https://www.protopage.com/tristan_berry04#Bookmarks
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