You can cancel the recurring payment for your Plan in the App Store on Mac.

1. On your Mac, open the App Store app.
2. Click your Apple ID at the bottom of the sidebar.
3. Click  View Information at the top of the window. You might be asked to sign in with your Apple ID.
4. On the Account Information page, scroll to the Manage section. To the right of Subscriptions, click Manage.
5. To the right of iStudiez Pro Subscription, click Edit.
6. Use the options to manage your subscription.
   If you cancel, your subscription will stop at the end of the current billing cycle.

Please follow this link to read more:

https://support.apple.com/HT202039