If you believe, as you evidently do, that the denial of benefits was wrong--that is, that under the plain terms of the policy, which is a contract, the insurer should have paid--you could sue the insurer for "breach of contract" for the money. If you prove in court that under the policy they should have paid, the court can order them to do so. That, a private lawsuit, is the only other option you have beside what you have already done: trying to work through the state's dept. of banking and insurance. Unfortunately, lawsuits have their own costs--for example, the cost of an attorney, unless you were comfortable representing yourself "pro se"--and you could spend as much or more on the suit than you hope to get back, with no guaranty of success (no lawsuit is ever guaranteed; do not believe any lawyer who ever tells you success is certain). Therefore, while you have the option of a lawsuit, it is not a very good option; you may not have anything you can effectively do but stay the course and see if the dept. can help you.