To manage your Apple subscriptions you need to use your Apple ID settings. There you can can cancel any subscription and trial subscriptions.
- Open the Settings icon on your iPhone or iPad and tap on your iTunes account or name in the upper part of the screen
- Choose iTunes & App Store
- Tap Apple ID
- Tap View Apple ID and Sign in with your iTunes password
- Scroll down and tap on Subscriptions
- Tap Cancel Subscription (you will receive a pop-up message to confirm cancellation).