Insurance and warranty disappoint

I am very disappointed with tje service i received from auto and general. I have a comprehensive and warranty policy with them,my car broke down last year september and they told me to take it to Bosch in klerksdorp after 2 months of struggle Bosch submitted a quotation,my engine was broken that it needed to be replaced and bosch continue to look for engine and they found a second hand one for R70 000,warranty of auto and general approved R6000 for rhe replacement now i was supposed to pay in the difference of R63 000 and to me that is like buying a new car.I asked them nicely ro give me the details of the dealership who sells the Audi A4 engine for R6000,and they couldn't.When i ask how is that possible for them to only approve that amount they said the engine is repairable ,they only write a car off if it is not repairable. How do you repair the pistons and injectors. If this is how they treat their customer then i don't support this kind of service. I would appreciate if they write this car off, I cannot buy an engine of R70 000 and risk not being coverd by the warranty.