You can simply deactivate your device by following these steps:
First, go to the My Vinli mobile app. Tap the Menu, then My Devices. Tap the device you wish to deactivate. Scroll to the bottom of your screen and tap Delete Device.
If you are a T-Mobile account holder, you will be promoted to cancel your service with T-Mobile. You will see a notification to Continue. Enter your 4-digit PIN and tap continue. Then confirm you want to cancel your service.
Please note, once your device has been deleted, your historical vehicle data cannot be recovered.