Dissatisfaction with third party nsurance claims

Their client hit my car at the back within weeks of purchase from a car dealer. I sent in all the needed document to process a claim. After weeks of endless writing to them, Kayara, they reluctantly send an assessor to assess the damage the market value of the car. They, Ettienne, wrote to me assuring that they will fix the car and the process is meant to put me back to the position I was before the accident as this was their policy. However, that did not happen. The assesssor wrote a report that says, the car's market value is R100 000 and the value for fixing it is R135 000, there fore it should be deemed a write off. In the light of all this, I should be given at first R88 000 and later R80 000 to go and fix the car. I argued with them that the car was bought in January for R170 000 and even at the time of writing this review, the car ranges between 151 000-170 000 depending on the seller's price choice. The car, Mercedes C200 automatic/ Elegance was bought in mid January and was hit on March 3 2019. Its value could not have gone down so low. Even how do I fix a car for 80 000 when they say the actual cost is for this is 135 000? When I tell them of my dissatisfaction, when give me a take it or leave attitude or I can take the matter to other platforms because what they are doing is lawful. How does this decision put me at a place I was before the accident? All I want is my car to be fixed by these people as they said they would at no cost to me.