Bad customer service

Bodytech 2000 completed a repair job on my car. There was the usual poor communication. Several weeks after getting the car back (with a lifetime warranty), I revisted the shop a few weeks later. The bumper they had fitted was coming loose. Brandon Ebden assisted me and I waited while the workshop refit the bumper. Now the bumper came loose -- completely -- after minor connection with the sand on an uneven road. The company's director (Karam), who the techhie referred the matter to, flatly refuses to entertain the issue at first. Then he refuses to give me information about the proper channel for complaint (company or industry level).