There’s two answers to that. Number one, if it’s the other party’s insurance then you can file a lawsuit, bring them into court and go after them. If it’s your insurance, and they have a legal duty to pay you and if they have refused, then you can sue them for what’s called “bad faith”. So, what you would be able to recover is damages for the underlying contract amount and then extra contractual or punitive damages for them refusing to pay a valid claim.
Our law firm handles those types of claims on a regular basis. Often times you have to bring those insurance companies into court in order to make them be fair with you.