You can cancel your subscription in the app by navigating to the Shop tab -> Manage Subscription. Select the subscription you wish to cancel and select Cancel.
You can also cancel your subscription at any time by pressing the SOS from within your vehicle and speaking to an Agent. Cancellation requests will be processed in the month they are received and services terminated at the end of that same month. (Example: If a request to cancel service occurs after the start of the month, services will remain active until the end of the month at which time they will terminate.)