Extended motor warranty Hollard refusing to fix my engine.

Wow. I have experienced a problem with my car where it overheated within a minute and it mixed oil with water. Apparently after the assessor, assessed my car, he discovered a whole on one of the pipes ad said it caused my car to overheat. Now hollard is claiming that they wont pay for the engine cover but they can only pay for the overheating. My question is. What if a stone went under the car and caused the damage and better yet what if a metal made the damage? I am paying hollard on time month to month but better yet they rather settle for a small amount and not fix my engine. They only say they will cover the overheating not the engine. On my policy they cover me for the engine as well but they are refusing to pay for my engine. No one knows as to what caused the whole but yes it caused the car to overheat and mix oil with water. How come do they hollard refuse to pay for the engine? I need help in resolving this issue with this company please.