Denying to pay claim for damages due to negligence on their site

On our way back from Potchefstroom on 23/08/20 kula stop n go just outside of Smithfield on your way to Rouxville we had an accident due to rocks that where on the right of way andy car was damaged. Mags broken, mirrors, scratches on the body. On our return to Komani took it for inspection at Car Service City and the total damages ( samp, bolt and cv joints, shocks and many more) will cost over R30K and mags and tyres over R11K. We were advised to submit a claim to WBHO Construction and Projects which I did, but the declined and refused to take any responsibility. They had said they will investigate, but no investigation was ever done. We have witnesses on site who are willing to testify in this regard. They must please supply the investigation report.