Classic Home Theater

Last year we hired Zach because he set up the home theatre for the previous homeowner. We wanted him to put our TV on wall and connect to the speaker. Zach came and did estimation and talked us into buying two outdoor speakers. We agreed. They came to our house and finished the work in two days. But
(1) they missed one screw from the TV stand when they uninstalled and
(2) made scratch on our newly processed hardwood floor.
Then the unpleasant experience began.
My wife gave another screw to them so that they can find the correct one and they said they would call a floor company to do the estimation. However, after a few weeks, it was really hard to reach them. Finally Zach came to my house and gave me some screws which does not fit at all and he missed the one my wife gave to him. And he told me the floor company does not call him back and promised to follow up. Then I made a mistake to give him another screw and hope he can find the right one. A couple of months passed, there was no news form Zach. I found that Samsung parts department has the screws and sent Zach the phone # to order. But he did not reply.
Now we missed 3 screws for TV stand and had scratch on the floor. It has been more than half year. Zach does not reply email any more. I feel like we are not fairly treated. All in all, they do not pay attention to details and will not respond if something wrong.