The worst experience I've yet had with a technical security firm

My problem is with the technical security side of Cap (Cap Security Systems) and not with Cap security: They were called out to do a job in November, 2022 because 2 cameras in my system were not working. The diagnosis was incorrect: I was told I had to buy 2 new cameras, which I did, but the problem persisted. I then came up against a wall of silence, as they failed to respond. I had to beg and threaten just to get a response to my emails (eventually I sent the email to 5 different staff members). Then the process would begin again: Technician comes out, fails to fix the problem, I again have to beg for a response to my email. In the meantime I’d paid R3500 for the misdiagnosed job. I then was told that I need a separate power supply for the cameras, and an additional power supply was installed, at a cost of R1150. I did some research on the item, and it appears it can be bought for less than R300 on Takealot. When I inquired how they could justify this overcharge, the response eventually from the operations manager (after further failures to respond) was to inform me that their technician had actually brought an entire case for the power supply (which together with the power supply itself costs more than R1000). When I asked where this additional unit is, I was told that the technician had removed the power supply from the frame, but had left the rest of the frame on-site, and that I had been charged for both. This is simply not true, no such frame was left on-site - When I pointed out that no such frame was left on-site, the technical manager’s response was that he believes the technician rather than myself, implying that I am lying. This insult to a customer is simply astonishing. It’s now 3 months later and more than R4000 spent on this job – and the problem has still not been properly resolved. I can certainly say that this is the Worst experience I have yet had with a technical security firm. It’s a great pity that the technical side of Cap is linked with the security side – I have nothing but praise for the security side, but this capsecuritysystems is a sad joke.