You can cancel the paid functions from the App Store or Google play where you have registered.
Google play
We use the automatic renewal function of Google (Google Play).
Please cancel your subscription from the following Google Play website.
To cancel, pause, or change your subscription on Google Play
If you are unsure of the cancellation procedure or are unable to cancel, please contact Google Play support directly.
Google Play Help
App Store
We use Apple's (App Store) automatic renewal function.
Since we are unable to cancel the plan, please go to the following Apple page to cancel your subscription.
App Store - Check and cancel your subscription
If you are unsure of the cancellation procedure or are unable to cancel your subscription, please contact Apple Support directly.
Contact Apple Support