Contaminated Diesel Bought From Sasol Garage

After two weeks of buying my car, my dream was short lived. The car broken down and it was towered to Nissan IC Auto Benoni where they found that the car broke down because of the diesel contamination which I bought at Sasol Bethal which damaged the Catalyst Convertor. The car was repaired which cost me R69 500. I made a claim with Sasol and provide a fuel Test result which confirmed that the diesel was contaminated according to Nissan. They investigating and I was asked to provide proof that I bought the diesel From Sasol which I did. Sasol send someone to get the Diesel sample from my car to do tests while the car was still at the repaired centre which till now I don’t know what they found on they are own diesel testing. All I know is that I was asked where did I buy the diesel before Bethal Sasol garage? Guess what? I bought it at Sasol Boksburg on the day I collected the car which it was almost empty when filling. Now they tell me that the diesel that they tested on my car had more PPM that the one that they are selling, where else could I have bought the diesel from? Which I told them they I only had the car for two weeks and I only filled at Sasol, which they ask me to provide my credit card statement from the day I bought the car which I did and it proofs that I only bought the diesel since having the car at Sasol garage only. Now they started saying maybe the contamination came from the previous diesel purchase before buying the car. Then asked if that is the case why the car did not brake then? The car did not brake after filling in the first time at Sasol Boksburg even when the car was almost empty in fuel and decided to brake after a week of driving and filing at Bethal Sasol garage. How is that possible? I did not get an answer. Now they started asking for a diagnose report of why and how did Nissan know that they need to change the catalyst Convertor? Which I asked at Nissan and they provided the Fuel report again. Now they asked me to ask Nissan if the Fuel pump and the injector where tested and they want proof in writing which now Nissan said No ways they will provide that. They told me to tell Sasol garage that if they want the tests that they want I want give them the car and do the tests by themselves. They will not intervene in this query which I did and reply to Sasol till now I have not heard from Sasol ever since. My car is ready for Sasol if they want it to do the tests. Now I feel that Sasol was try to play me for a fool making me jump thru hoops until I get tired and drop this issue since it is taking more than a months to investigate. I will not drop this issue until I get my money, I will not be blamed for something I did not do. Sasol must give me straight answers about my query.