Shoddy workmanship!

I bought a house a sky city, was very happy with most of the things besides a few minor things on my snag list. Then 3 months later they call me to say the will fix the things with what they call Retention. A guy called Mr Mathata came in and fixed some if the things. 1 of the things was a huge mark on the sink. So he used some red acid with a pot scourer then removed the mark but left me with an off black sink with so many scratches, it looks worse than your worst Hart pot!! Then I told him I was unhappy about it and left on day 1 without making me sign, I told them I would not be available the following day but they instisted that iy would be fine as long as there is someone in the house. They came the following day knowing very well I was unhappy with the sink!! and made my house mate sign off the jobs knowing very well it is not his house and he explicitly said to them I am only a house mate but they said he should sign anyway. Now I'm left with a terrible sink while Mr Mathata and Cosmo are telling me about George's signature. WHY CAN'T MR MATHATA BE HONEST ABOUT HIS SHODDY WORKMANSHIP? AND ABOUT OUR DISSATISFACTION? WHY DID THEY FORCE GEORGE TO KNOWING VERY WELL THAT WE WEREN'T ENTIRELY HAPPY?