unreliable

I have insured my cars sound system and when I made a claim it was not approved because its wear and tear i could not believe i had to pay the sound guy to check out after I mentioned many time that the amp burned and the speakers blown i had to get it for the professional guys and it was still decline when I called a other insurance company i was told they cover whatever damages so I won't insure with them what if my car had to burn out what would the out come be