Unsuccessful CCTV camera and intercom installation

I bought 4 wireless CCTV cameras and an intercom system from Willy de Beer from WC systems/RD systems. It took a long time to install the cameras, but after a day or two they would go off and we would have to start again. As he could not fix they problem, we eventually had to get another installer to redo the system. The intercom never worked 100% and we had to replace it at our own cost.