so my phone was at about 70% charged and pluged in. I was on FB messenger typing a message and all of a sudden it turns off, starts back up, gets to the ZTE screen and then shuts off again. Now it wont respond at all, it doesn't even light up when pluged in. ive tried to reset it, ive held the power button + volume up for 2 mins, enven let it sit for an hour on charge. plz help me, or am i gonna have to buy a new phone?