went for a purchase, left with damage

On Friday, May 17th, I went to Midas Bellville to purchase shocks for my vehicle's canopy. I bought the recommended product, and one of the employees was tasked with the installation. Since I had to run to another store, I asked my wife to assist the employee by holding up the canopy door for him during the installation. When I returned, I noticed that my canopy door was completely askew. Upon lifting the door, I saw that one of the hinges had been completely bent and torn. My wife reported to me that while the Midas employee was doing the installation and she was holding the canopy door, at some point the employee lifted the door from her hands with extreme upward pressure such that she could no longer reach the door to lock in the ball joint of the shock. After the installation was completed, she asked him why the door was skewed, and he told her it was because one shock still had the old joint while the other shock had the new joint. I went to the manager to report that the shocks were negligently installed, causing damage to the canopy hinge and risking the door breaking off. The manager merely shrugged his shoulders and said he would refund me for the shocks. When I inquired about repairing the damage they had just caused, he shrugged again. So I left without the shocks and with damages that I am not responsible for, facing the time and cost to repair it.