I've had this phone for about 4 months now, it used to reboot on it's own earlier but lately it's been powering off not coming back on as a result of which ive been missing calls. I don't think it's the battery and I don't have any games on it. I have done a reset twice but that dint help either. I live miles away from any accessible metropcs store to bring it to them. Is it defective, what should I do?