I checked the yellowpages, there's only one telephone, to which I tried to call and complain. It's that guy answered the phone ... I believe that's a family company and the guy is the boss indeed. (I don't think I can get to his "manager" later.)
The purpose I wrote it down is just to warn everyone else so that we don't have to suffer that kind of bad service.
Thank you very much for your warm-hearted suggestion. Have a nice day!