Cancellation for an app-only subscription must be done on your iOS device through the app store.
You can see a guide from Apple on how to manage your subscriptions here.
Alternatively: You can reach the subscription management controls by opening the "Help" Tab in the Hydrow app and tapping on your Digital Basic subscription status at the very bottom of the screen.
Please Note: Because this subscription is managed through the App store the Hydrow Customer Care Team does not have the ability to make any changes to your subscription status or refund any charges from the Digital Basic subscription.