my brand new lg phone has been working fine. suddenly today while i was texting it stopped getting a signal. The rest of my family (who are on the same plan) all had and still have full signal, while i have none. i tried restarting the phone several times, it did not work. I also put my sisters sim card into my phone and got a signal while it was in it. After i removed her sim, my phone now has one bar of signal, but does not say att&t and will not send or recieve calls or texts.
Go to AT&T and request a new sim card. they will give you for free. and if this does not fix the problem go to apple to the Genius bar have them look over the iphone. make a appointment with the Genius bar.