Unfortunately, Apple does not give developers any control over your subscription or billing, so we are unable to cancel for you. However, Apple makes it pretty easy to manage your Nomorobo subscription from your iPhone. To cancel your subscription, please follow these steps:
1. Go to the Settings app > iTunes & App Store.
2. Tap your Apple ID at the top of the screen.
3. Tap View Apple ID. You might need to sign in or use Touch ID.
4. Under Subscriptions, tap Manage.
5. Tap the subscription that you want to manage. In this case, Nomorobo.
6. Tap Cancel Subscription.
-For more information please check out Apple's Support Page by clicking HERE
Important: Uninstalling an app will not automatically stop your subscription. You must cancel your subscription to end your subscription. If you uninstall the app without canceling your subscription, you will still be charged.