Follow these steps to turn off your auto renewal on your iPhone:
- Launch the Settings app on your iPhone.
- Tap on App Store.
- Tap on your Apple ID at the top of the screen.
- Tap View Apple ID from the pop-up menu.
- When prompted, enter your password, and then tap OK.
- Under Subscriptions, tap Manage.
- Tap the name of the subscription that you want to modify.
- Turn the auto-renewal option to Off.
- Tap Done to save your changes.
If you would like further information or assistance, please contact Apple directly at: https://support.apple.com/billing.