You can cancel at anytime. Log in to fullscreen.com from your computer, then click on your profile picture in the top right-hand corner of the screen. From there, click on “account,” and go to the section labeled “Your Plan.” You can deactivate or delete your membership from there.
If you signed up through your iTunes account, you will need to manage your subscription via your iTunes Store account. Please follow the instructions here to cancel your subscription
If you would like to cancel from your Android device, go to the settings cog in the upper right hand corner of the Fullscreen app. Then go to Subscription Info > Manage Membership. Select the version of login that you used to create your account, then click on End Membership. This will cancel your account.
After you cancel, your membership will be active only until the end of period for which you have already paid.