Motorite do not pay

I bought a car on the 10th of December for ZAR 75,000. The dealer urged me to buy a motorite insurance as well although I didn't want. On the 12th of January, after 1000 kilometers the engine broke. I informed motorite and the dealer at the same day. The car was towed to the dealer's favorite mechanic, who has also done the last service. The quotation for the repair is ZAR 33,000. On the 18th February, after two months (!!!) motorite sent an assessor and now motorite wants to pay only ZAR 2,000 because they say overheating was the reason for the damage. Today I asked for the assessor's report and they want me to sign a paper, that this report is confidential and I may not show it to any other person and that once I got this report motorite will not accept any other independant assessor. Without signing I will not get the report. Is this legally? In other words I think: The dealer works together with motorite, forces the customers to buy an insurance, motorite does not pay and if you want to see the report you may not use it. That's how they bypass the consumer act.