Phone gets no network coverage

I have a Nokia N95, my son dropped it a few days ago, now I get the 3G signal, it connects to the internet, and I can do everything, but make or recieve calls and messages. I get the 3Gsignal, but no bars. I contacted my cellular company, and they said the service is on, and they don't know what is wrong. I then took the phone into the company, and they can't figure out what the problem is. Can yo please help me?? The phone is in excellent shape. Have done a master reset, and still nothing... Any suggestions? Thank you!!!