Ruined due to car wash

The car wash at the Engen Mimosa ruined my car's roof lining. I've been going to the garage to speak to the owner / manager by the name of Mohamad but he's never available, I've left my contact details about 4 times already and he's never bothered calling me back. To fix my roof lining is quoting me around R4000 and I can't afford to pay for someone elses mess up.