Warranty vehicle repair desputes

Concerning repairs on Ford st 1.6,gasket blown and cylinder 4 cracked, they didn't send an assessor and ruled that my car was overheating based on the pictures report send to them by garage and authorized R6000.00 which is not even covering any damaged part on the vehicle. The car is been in garage for almost 2 months.They refused to send assessor to make a comprehensive report and told me is common for Ford cars to overheat.The process of administration was not followed and there is no proof to determine the cause of the damage.