Miway is doing things 'Theirway'.....

I had an accident claim on my vehicle. A tree fell on my car. Their customer service is not existenting. After two weeks of registering the claim I had to phone them for the second time to settle my claim. They don't phone back even when they promise to do so. And then only to find out that they are only willing to settle 24% of damages on the original market value. Premiums are paid out in full and even though I decided to take the comprehensive cover they are only willing to settle 24% of the damages. Please explain to me how this is lawful.This is totaly unacceptable!