Rude and no clue on profesionalism it is a disgrace

We were driving from O.R Thambo airport. I was driving infront in my nissan 4x4 and my son behind me in his kia rio on the R24. There were a piece of truck tyre inside the road, i wanted to brake hard as not to drive over it and sa in my rearview mirror there was another vehicle between my son and i and saw if i was going to brake the car behind me is going to modify my rear of the bakkie. I swerved left missed the tyre and came back into my lane. Ilooked behind me to see the car behind me me stopping and my son behind the lady. I did not see her car budge forward at all and she stopped right before the tyre and assumed my son did not hit her. I pulled off the road and found my son did as in Really touched the lady,s car. No damage at all my sons kia no damage nothing but i still informed my son to exchange details and to report it to the police within 24 hours. Which he did 2 hours later in meyerton. My son received a mail for costs for replacing front and rear bumper a light magwheel repairs, repairs on the inside of the bootlid, splash cover plate replacement etc. We contacted outsurance and said it is a false claim as there were no damages to any of the vehicles and asked them to investigate as he is not going to pay that and they can even see on the photos that it is impossible for all that damages and the rear bumper still fully intact. We received threatening letters from outsurance and even asking the agent for all his details and the head offices number we only got snotty remarks back. It looks like Outsurance is supportinf *****ulant claims and dont care about anyone. It is a disgrace. I hope outsurance is seen for the ***** they are.