Your rights depend on two things: the terms of the policy and the applicable law.
You need to see a copy of the policy to know what the insurance company is obligated to do, and at the same time you can learn what you have to do to qualify for benefits.
You also need to know if the policy is governed by ERISA, which is a federal law, or if it is governed by state law. If your policy was provided through work, and you did not work for for a governmental entity or church organization (i.e. you worked for a private company), your policy is probably governed by ERISA. If so, then the insurance company has certain specific requirements and duties it has to meet in making a decision on your claim and the handling of it in general. If your claim is not governed by ERISA, then your claim likely is governed by state law.
The applicable law can be very tricky, but also very important, so it is important to speak with someone who deals with these types of claims if you look for someone to help you answer this question. There are times when the applicable law determines whether I take a case because of its importance.