Filled petrol instead of diesel.

I went to Engen Midway Mews to fill up diesel but the attendant filled up petrol instead and then covered it up by filling diesel afterwards. I then left the garage and after driving approx 4km the car switched off. Paul van Staden (Engen Midway Mews Manager) accepted responsibly and agreed to cover the repairs and a rental car and said if the costs exceed R7000 it must go through his insurance. Costs were higher and it was sent to Hollard insurance on the 17/02/2015. Hollard assigned an assessor in the wrong region and the correct assessor only assessed my car on 03/03/2015. The rental car bill in the meantime accumulated to R9320,92 and the garage owner refuses to pay and Hollard say they do not cover him for 3rd party claims. I now have an outstanding rental bill of R5676,92 which I had to pay for so I gave the car back. My car is still not fixed a month after the incident and I have to make alternate arrangements daily to get to and from work, inconveniencing other people and costing me time and more money.