NETSTAR BAD SERVICE

I have a big big problem with NETSTAR. The first time they install the cameras in my trucks,it started with the problem of working, not working. I let Netstar in Bloemfontein know, the guy there was Franscois. They send somebody out, but there technican was brakeing my dashbord and try to fixed it with cableties. In March people of Bloemfontein came again and make some notes of the cameras that didnt work. Still no one call, no one come to fixed it. I phoned headoffice in Johannesburg to report, and also no replay. But they just keep sending me statements. How can we pay for no servive. Please Help