How do I unsubscribe to an game app

There is this game called school of dragons( sod) , can't seem to find contact info to correspond with them, I would appreciate some specific info on how to unsubscribe. My son signed up for an automatic pay, I have tried everything to

Unsubscribe and can't get in contact with them. I know it's probably to much to ask but I would be in your debt if you could help. Thanks so much.

Thank you for your reply but when I go to that my Apple ID there is no option for subscriptions