Refuse to fix my car

I joined oakhurst insurance last year around November on Mechanical warranty, My premium is R280.00 per month, i joined this cover telephonic-ally and i was told that their mechanical cover covers everything to do with the engin, but not the suspension of the car( yes i understood). But now my car's radiator( engin cooler) is not functioning well. I then put on a claim then i was told to do the quotation and also send the full service history of the car, then the next day after i have send everything they requested i received a call from Sara telling me that they cannot fix my car. why they wanted me to make qoutations while they know they wont fix my car. If they dont want to fix my car it is better they pay back all my premiums