Unprotected loads caused damage

One of the company trucks travelled from the R55 and turned into Lochner rd , Centurion. The truck had some rubble left over on the bed which bounced off the truck as far as it drove. This caused damage to our vehicle on the windscreen, bonnet and bumper. We took a photo of the truck and apon calling the company we were informed that they cannot assist. We can contact their insurance but they are not covered for such claims. We spoke to a Manager a couple of times and only received a cold shoulder. What is strange though is that this is a flatbed truck for loading equipment and vehicles, yet it had rubble on it. Clearly a misuse of the vehicle to what it was designed for. This is definitely not a company that respects other road users or their equipment.