Repairs, Servicing and Bad attitude

Good Day<br> <br> Myslef and my wife took our car to Hyuindai Bedfordview for inspection/diagonis following a click click that the car was doingb when one start it and also the water leakage, later when we go to collect the car we found out that they have not assembled it yet around 17h18 pm, we waited until they are done, A week later a car could not start and we call them , they dispatched a tour truck that came and tour the car to their garage, few days later they send an email saying that the earth cable was not fasten properly causing an open circuit on the car which looks like someone worked on the car, to my surprise is only them that have been services that car, they then request that we must pay for the tour charges and the repair on the vehicle, Why must we take responsibility for their negligence?<br> <br> Regards<br> <br> Emmanuel