3 times and still not right

And I quote "one solid membrane that stretches up to 10 times its size", so I had my complete tiled roof in St Francis evaluated, and as the applicator was happy, I accepted his quote and he went ahead. In doing so he used more of the coating than he quoted for, and approached me to cover this additional cost of material, which I did. But, the coverage was not continuous so he came back for the first time and recoated where necessary, but unhappily so. Again the coverage was not continuous, and after much effort, he came back again, and assured me that the coating was now continuous. In the interim he did further work on the house, away from the roof, and upon inspection of the new coating, I found that the now twice repaired coating is still not continuous, and we now have a leak where there wasn't one before. Photo's and messages are ignored, so I wrote to his partner in Port Elizabeth explaining this concern, and his solution was not to engage the problem, but forward the emailer to the applicator who has no interest in resolving his substandard workmanship. All I want is to get the continuous coating as was quoted for, and paid for ... nothing more