If you want to stop your subscription then this is easily done through apple.
Unfortunately we have no control over payments. You only need to cancel through apple, you do not need to cancel your subscription on the app itself.
You can do this on Apple here
Subscriptions may be managed by the you the user and auto-renewal may be turned off by going to the your account Settings on apple after purchase.
Go to the settings page and click on Subscription manage in iTunes.
This will take you to the iTunes store account page where you will be able to cancel your subscription.
Currently we allow you to login and view your data, alongside export a copy of it even if you do not have a subscription. Before you stop your subscription we strongly advise you to export your data as a spreadsheet and report.