If you first signed up on the website, then you will need to cancel your subscription by logging into your account on the website.
If you signed up via an in-app purchase, then all in-app subscriptions are managed by Apple, Google, and Roku. To cancel your in-app subscriptions please follow the instructions for your device below:
Head into your settings on your phone > iTunes & App Store > Click your Apple ID > View Apple ID > Subscriptions > Cancel Subscription
Open Google Play Store > Tap Menu > Account > Subscriptions > Find the subscription you want to cancel > Cancel Subscription
To cancel your Roku subscriptions then please follow the instructions below