I have a brand new Samsung SGH-U700, Ultra Edition II. For about 3 weeks, i've been using the phone without a problem, then recently, a little icon appeared on the screen, resembling a little telephone with a cross over it. Since then, I haven't been able to make or receive calls or texts. I've tried call barring, but can't seem to figure it out. When I transfer my SIM to another phone, it works fine.

Any help will be appreciated ! Thanks !