i have had my phone for almost a year now and earlier i was texting it said low battery and then like 3 txts came in at the same time then all of the sudden the screen turns black and once about every 5 mins the screen turns on but the keypad doesnt work then about an hour later it altogether wont work unless someone txts or calls then the screen is on for 30 seconds and the keypad still wont work please help!!!!!!