Hey Can you help? I have an iphone 3GS, about 2 weeks old, on O2 contract. I've experienced no problems, until today, where i keep getting "No Service" in the top left hand corner. It keeps going on and off. The only thing I can do to make it back it turn off 3G, and then turn off the phone then put it back on again, but it just gradually goes down to no signal. Any tips? Thanks, Sophie.