Plumbing and electrical certificates

Selling my flat I was asked by the estate agent if he could arrange the certificates I needed . I accepted as I had bought the flat 11 month previously and had received compliance certs from a plumber and electrician on purchase. Not having changed anything I assumed the fee of 300 rand per cert would be what I was charged.<br> I received a quote of 2900 for various works that was needed to issue these certs. I inspected the electrical part and found for one missing label 3 lamps (not part of the safety ) that had to be replaced and a loose earth wire he wanted 900 rand. The plumbing was 2 small works of moving two pipes with vacuum 300 mm away and buying a 80 rand water drain. I immediately investigated and found that my previous cert was still valid for electrical. I then accepted the plumbing part of the quote. The cert was then issued . On inspection I found the work as quoted ie moving the vacuum breakers 300mm away was not done . Extreme plumbing then billed the transfer advocates the full amount of 2900 to deduct from proceeds of sale. I stopped this but Jean Cloete still insists I owe him the money as although hi did not complete work as quoted he did do work and issued the cer