GOOD INFORMATION FOR YOU AS A SPECTRANET 4LTE USER
Please TRY always off your device by your self, DO NOT allow the battery to stay on till it runs out and off itself as this has damaged many user devices without notice (EXCEPT THE DONGLE AS IT DOES NOT HAVE BATTERY IN IT) and spectranet has no repair unit or people to reprogram it. this means when it happen to you then you have NO OPTION BUT TO BUY NEW ONE.

(it happens to me when I still have 15gb with there network)

THEY WILL NEVER TELL YOU THIS,