Bad service from A24/7 Electrical and Plumbing ( Pretoria)

Phoned Martin to do my COC for house. They did the inspection and asked R650. Then they said that there are a couple of things to be fixed. The quote came to R4945. I asked if I can get my own quote, which they agreed apon. Another company qouted me R1700 for the same job. After they fixed all the problems, noted by above company, I phoned Martin to inspect. He said that he can not inspect another company's work and that I must ask them to issue a COC. Martin should have told me the day he did the inpection and why did he quote so much? Will never use them in my lifetime and I want to warn other people not to fall in the same trap as I did.