In many states, but not in mine, there are laws that require insurance companies to investigate and settle claims "in good faith". I believe these statutes are part of a "uniform" set of laws similar to those governing commercial contracts and child support payments. Usually the state's insurance comissioner has a complaint office that will do the investigation work on behalf of a consumer. I'd check with your local gov's websites and see if you can register a complaint against the carrier. Even if it doesn't affect you directly, a history of complaints by consumers against a carrier might have consequences in the future.