Poor service and I'll treatment of staff members

Had a bad experience at Dunlop Zone in Midrand, the Manger is very disrespectful of his customer and staff members. He threatens his staff members in front of his customers. Just today I left my car at his care as I bought tyres and the needed to install them and do wheel alignment... I gave the keys to him and went to the nearby shops as they were busy with the car. When I came back my boot handle was broken and the manager told me it's not his fault that his staff that were working on my car could've broken... What hurts me is that my keys I gave them to him, and he assigned someone to work on my car, so he is liable for the damages on my car