panelbeater who damaged my car

I put through a claim to king price insurance who then referred me to their approved panel beater Milano in Pretoria west, a silver AUDI A3 TDI, the insurance process went smooth with assistance from Mohamed who has been very helpful and professional, BUT yesterday on arrival to collect the car from the panel beater, my key holder was missing and with attitude I was told that they (panel beater)are not responsible for missing items in the car, ok I ignored that, after driving the car for about 10km the car then started licking oil which t me was and funny noise started coming out of the car, IF the car went for body works why was the bonnet opened and I noticed that some boats were not fastened properly, the car is currently at home packed because of the leaking oil and I'm not comfortable in taking my car back to them because I noticed that they tempered with lot of items in it, who should be held liable? I don't have any contractual binding agreement with Milano, is this what they do to people who bring their cars in for repair. I am totally dissatisfied and unhappy with them. what do I do because my car is stacked???