Go to My Account on your Parent Dashboard and select Subscription Summary. From there, select Deactivate. This will automatically deactivate your credit card from the next billing cycle if you have signed up via our website. If you signed up in the App Store, on the parent device, go to Settings > iTunes & App Store. Tap your Apple ID at the top of the screen and then tap View Apple ID. You might need to sign in or use Touch ID. Tap Subscriptions, then tap Forcefield and cancel.
If you signed up in the Google Play Store, from the parent device, select Google Play Store > Tap on upper left "hamburger" menu > Account > Subscriptions > Find Forcefield for Parent Device > Tap Manage > Cancel Subscription.