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

https://sierra-wiki.win/index.php/Why_Does_Apple_Make_Me_Request_a_Refund_Separately_From_Canceling%3F

If Apple billed your SuperGrok subscription, go to reportaproblem.apple.com to request a refund. Just canceling the subscription in iOS Settings won’t issue a refund automatically