ADT is avoiding responsibility

ADT sold/rented an alarm system for my premises a couple of years ago. This alarm was tested numerous times by ADT, and declared fully functional every time, until a little less than 2weeks ago. That same system is now allegedly not installed correctly and should not have been installed like this in the first place. ADT's technician has disarmed a section of this system now. In the meantime my family and I have been living with this dysfunctional alarm for longer than 2weeks. I'm currently paying good money for this bad service, needless to say its unsafe. I have made numerous calls to the Vaal branch and left many messages for the Technical Manager (was advised to do so) but no responds.