I have the same problem, but my phone has a built in battery and I can't seem to get it to "power off". The has happen to me once before but the only solution that ever worked is to wait till the battery died and charge it again and then it reboots, but I need it to unfreeze quicker because i am in need of it right now.

Hi Melissa. You can simply remove the battery then put it back in. Turn on your phone and your phone should be back to normal.