How do I turn off auto-renewal?

No matter what device you're using, your subscription's auto-renewal will be managed outside of the app. Here’s a step-by-step guide:

(Don't worry, your number will still work until the end of the billing cycle!)

iOS :

• Go to Settings > iTunes & App Store.
• Tap your Apple ID at the top of the screen.
• Tap View Apple ID.
• Tap Subscriptions.
• Select the subscription that you want to manage. If you don't see any subscription but are still being charged, make sure that you're signed in with the correct Apple ID. 
• Tap Cancel Subscription.

Android :

• Open the Play Store.
• From the main page, tap the menu icon in the top left corner, next to the Google Play text.
• Tap Subscriptions.
• Select the subscription that you want to manage. If you don't see any subscription but are still being charged, make sure that you're signed in with the correct Google account.
• Tap Cancel Subscription.