You can log into our admin website and click Dashboard
Scroll through the list and find the device that matches the one you wish to deactivate. Both the Device Name and Mac Address (Code) will be visible on the bottom of the login screen. Once you found the correct device, click the Deactivate button.
You can reactivate this device at any time by selecting the "Show Active Only?" Checkbox and clicking Activate. More information on how to do this can be found here.