Speak with a professional

It is also a good idea to check with your health care and ask to speak with someone who specializes in the treatment you receive. After all, he or she can be very personal assessment of your claim, you can ask specific questions about what may or may not be covered by your policy. For future reference, write his or her name and phone number at the beginning of the call. Keep detailed notes on what is happening all over and keep all related paperwork, even if you are not sure whether it is correct. Include in your notes:
-Once the required treatment prior permission was sought and received and from whom
-Date of treatment
-What has been discussed with the doctor, what action was taken and what follow-up,

Unfortunately, errors are common in claims. A 2002 study of America's Hawaii Health Insurance Plans, which reported that 14 percent of the requests for insurance was rejected. The same study showed that one in seven claims to be processed again and again due to errors in the original claim, a costly process for all concerned.
Other things you can include:

Research your state laws about what needs to be covered with a claim and what the law considers "arbitrary". This would affect an insurance company the definition of "medical necessity" and billable requirements.
-Make sure your doctor and insurance office is in contact with each other and that all necessary documents are sent from one to another.