How to cancel or edit an iTunes subscription with iOS - Instructions
1. Launch the Settings app on your iPhone or iPad.
2. Tap on iTunes & App Store.
3. Tap on your Apple ID at the top.
4. Choose View Apple ID from the popup menu.
5. Enter your password if/when prompted and tap on OK.
6. Tap on Manage under Subscriptions.
7. Tap on the name of the subscription you'd like to cancel or modify (if you have more than one subscription).
8. Turn the Auto-Renewal option to Off.
After your current paid period ends iTunes will no longer bill you for that particular subscription. If you ever decide you want to re-subscribe you can do so either through the app or by turning the Auto Renew option On.
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