Genric Warranty

I bought a car last year with Genric mechanical warranty which is suppose to cover me for 2 years. My car over heated and damaged the engine then I took it to Bosch workshop they diagnosed my car and they gave me a quote that is R82000 for my car to be fixed. I forwarded the quote to then Genric warranty they told me that they can only pay R3000 for the car that overheated. They even asked for the three service proof . I gave them. I never missed a service. whats the reason to have a warranty that wont cover your car in the event that you need them most? I'm paying a care that is now is packed at my Garage that is still covered with Genric Warranty.