Builders warehouse truck damaged my Mercedes Benz

A few months ago my wife and I were on our way home and we were stationary at a stop street in Canal road Wetton when a Builder’s warehouse tip truck with stones on the back was turning into Canal road from Plantation road and a good couple of stones came across the car as there was no cover over the stones. The truck driver just kept on driving and we were in shock. We then stopped at the Wetton branch of builders and ask the manager if it was their truck and he said it was a truck from the Tokai branch. I then asked him to come outside to see what damage was done by the stones. He noted a stone still stuck in the boot and the rear window I got all the details from him and sent Tokai branch the pictures and quotes for the damages. It’s been more than two months and they have now told me a few weeks ago that they have handed the matter to their insurance company and to date I have not heard from either I drive a Mercedes Benz which I paid cash for and I am disgusted by this company who cannot even attend to such a small matter