Give me back my Alarm system

I was an ADT customer for many years after a certain incident (no response) I decided not to use them any more. I switched banks and there were some billing issues aswell. <br> <br> Anyway, they called me and want their Radio Transmitter back. Fair enough. Send a technician, take the radio and reset the installer code to something of my choosing. They refuse to do this. I have to seperately pay for a technician to come out to get control of the system that I own.<br>