Ask the customer service executive of the health insurance company about the procedure to make a formal appeal. You can also find the information on the company's website.
Draft and send your formal appeal letter, or create and submit it online. Write in-depth about the disease that the person was hospitalized for, the doctor's recommendation and treatment, medical fees and reasons for filing the claim. Furnish medical records that add weight to your appeal.
Draft and mail a letter to the head of the insurance company or any responsible high-authority employee if you feel that your case hasn't been given its merit. You can get the email address from the company's website where you can send an email to report grievances regarding your appeal.
Escalate the appeal to your state's insurance commissioner if you're not getting a response. Send a copy to the head or the respective authority employee of the insurance company. Attach previous correspondences to let them know how strongly you've pursued this matter.
Notify the local Better Business Bureau if you notice any discrepancies, loopholes or callousness in the way the company has handled your insurance claim. Maintain a record of all the correspondences; make a note of the dates and the people whom you talked to, so that you have a record for reference.