Samsung SYNC SGH-A707

I have recently got the A707 and like the phone so far. Except, for the fact that the phone does not ring when somebody calls. I use the factory installed tones and still no deal. When check the profile to see if the ring volume the ringtone is still muted. I exchanged the phone thinking the unit was bad but I just found my replacement doing the same thing. I am wondering if the this is a clitch that can be fixed or should I just get a another a707, or forget this phone and replace it with something completely different. Thanks...

--MB

PS: I am also wondering if the network it is on has an effect on it. It seems to happen when it is on the EDGE network. Possiblity???