Not fixing things that should have been done correctly in the first place

We used LXCOR to install a patio roof, sprinkling, a gas cage and a gate. After the sprinkling was installed, it was found that the sprinkler system did not function properly. I had to pay extra labour for them to dig up the system and add additional pipes. I had to call him back to fix my paving that he dug up, as it was sagging. Also, no paving sand was placed between the bricks. Our patio roof started leaking. I sent him a message advising him of my problem. He advised that I had to pay an additional R800 to fix it. He never installed a flash plate, which was causing the issue. I will not pay him another cent. I will use another contractor to fix this. We wanted to use them for other work, but ended up cancelling the rest.