Developers have no authority to either check or collect users' information and cancel subscriptions for users directly, users have to cancel subscription in their own accounts.
For subscriptions made through App Store iOS, please make sure you have login the right Apple ID which you used to subscribe and then go to the Apple ID in iPhone setting. Click “Subscription” to manage your purchases.
- Open the Settings app.
- Tap your name.
- Tap Subscriptions. (If you don't see "Subscriptions," tap "iTunes & App Store" instead. Then tap your Apple ID, tap View Apple ID, sign in, scroll down to Subscriptions, and tap Subscriptions.)
- Tap the Subscription you want to cancel.
- Tap Cancel Subscription.
- Tap Confirm when prompted to confirm that you want to cancel your subscription.