Has it ever worked? As well as formatting, you also put the all important "TeslaCam" folder?
Whats on it exactly when you put in a PC/Mac? Drive properties and top level folders useful to see - they may be corrupted.
USB socket/plugs also teem to be temperamental which can cause problems and corruption - latter is game over until a reformat. I could reproduce this at will on our car - I could turn Dashcam icon on and off just by slightly wiggling the USB plug - this can affect any device especially if its unsupported and 'flapping in the wind' - I velcro'd ours to underside of phone flap - problem solved.