Keyless entry issue

I lost one of my key fobs and I just purchased a new one. I tried to program the new fob, but the system would not accept it. I even tried programming it using the Tech 2, but still no success. I went to the dealership and they couldn't get the sysem to accept the new fob. The tech told me that the receiving module may be malfunctioning, but he could guarantee that replacing the module would solve the problem. How can I solve this problem? thanks