When your insurance company denies a claim, it's usually because the company decided that the claim was not covered under your policy. The first thing to do is call your insurer and ask why the claim was denied, and make sure there were no errors in how it was filed. Many denials are a result of administrative errors. If not, review your policy and make sure you understand exactly what it covers.
If you still think the insurance company should be paying out, you'll want to call them back and ask how you can start the appeal process.
If your appeals are denied, the next step is to contact your state regulator. Some states have an ombudsman who can guide you through the process. Your state's department of insurance will be able to tell you exactly how much assistance they can provide. To find out who to contact in your state, go to the National Association of Insurance Commissioners Web site. You will also want to file a complaint about the insurer at your state's department of insurance.