I am facing a very weird problem with my iPhone. I got the iPhone from AT and T and got it jailbreaked. After jailbreaking the iPhone, it worked properly for 3 days but now I am not able to make or receive calls on the iPhone.The phone gives "Network lost" error message while using the phone. Has jailbreaking blocked the phone from making and receiving the calls? Please suggest some solution for solving this problem. Any help is highly appreciated.