Bad service and overcharge for a not fully functional CCTV installation

Divan Nel of door24 installed a CCTV system that is not working properly. There is interference between two screens so that not all cameras do work. Extremely slow service. Overcharging: charges even if you just talk to him. He comes in for work late, never before 10 or 11 and then after 17:00 it is all after hours fees. Divan just left us with a set-up that is not fully functional. My impression is he cannot solve problems with his installation. He should therefore not do this work alone. It is unfair to be charged a huge sum of money for this and now he just stays away. He even went that far to say there is no guarantee at all on his installation because I have not paid in time but I did. This is surely not according to the consumer protection act. Divans business administration is extremely poor also.