Bought this phone in june and has worked fine until about 3 weeks ago. I do not download or add anything to it, just text, phone, facebook, and check email. I made a call 3 weeks ago and got a message that said not registered on network, tried to send a text and it would not send anything, tried to go online and would only go online if I turned on the wi-fi and put in my code for my home acct. The phone will work fine for about 5-10 minutes if I turn it off and then back on. Customer service has been unable to fix. They finally replaced the phone and about an hour later after activating the new one had the same problems with new phone. One tech said I was bouncing off the wrong tower? Said she fixed it, but a little while later - same problem. Now they want to send me another phone! Any ideas what is going on here?