The problems are possibly 2-fold:
(1) A physical fault with the USB socket or it's MO connection or a component failure on the board itself resulting in the flaky charging and non-reception of FM TMC [sometimes it can help to re-flow the solder connections for the USB socket, but if the problem is on the board then that won't help of course];
(2) The subscription for the smartphone link not being validated. Maybe it's the phone, easy to eliminate that by trying another smartphone. In some places Garmin ensures certain features are 'locked out' by Locale selected, and some factory localisations do that intentionally, i think maybe also some subscriptions are disabled too [?]. I effectively know nothing about the latter though. In some modern units it's possible to temporally change the locale via the hidden menu behind the Speedo [press 'Speed' field on the main screen, then hold the centre of the speedo for several seconds to access the developer menu]. Other units can only be hard reset and the new Locale selected on reboot. Clear NV in the hidden menu will even more comprehensively reset the unit. Worth a try imo.