Bp garage in Sunnyside Petrol station

On the 3 October 2021 I took my car to BP garage for car wash as they have car wash service.I handed the keys to the staff member I then left as it takes about 45 min to an hour to have your car ready.on my return they had just finish washing and wiping the car,I went I paid for services as I was about to start the car I noticed that the wind screen is cracked and has glass particles,I came out of the car I asked what happened to the windscreen nobody knows,I called for their manager who was inside,I came and he saw the crack along with pieces of glass particles,he then went to the camera that they have at the garage to have a view of could have happened,nothing was visible.he then said he will write a report and inform his boss of the incident.I left I came back on Monday of which I was told that he is the meeting.I left my cell no so that he could call of which he never did call,few days later after I went to the garage again he was not available but he left a message that he will not be held responsible for the windscreen. Please kindly assist so that it doesn’t happen to the next person because something did happen to the wind screen,and that if you are a business owner you give yourself time to attend to cases n where it die you pay for damages not to push the blame,I know for a fact that when I got to the garage the windscreen was not damage,and also if it was long damaged how was it that there were still glass particles on the car