If Apple billed your SuperGrok subscription, go to reportaproblem.apple.com to...

https://www.nav-bookmarks.win/to-cancel-grok-properly-you-need-to-use-the-same-billing-channel-where-you

If Apple billed your SuperGrok subscription, go to reportaproblem.apple.com to request a refund. Cancelling the subscription in your iOS Settings under Subscriptions stops future charges but does not refund past payments