First Priorty Health Question...(PA)

Has anyone been approved by first priorty health having only 2 supervised diets instead of 3? I am awaiting approval from the insurance company.  Also can you still used information even if it's been purged?  Explanation: I went to a hosipital dietician 15 years ago, however the hosipital and medical billing only keep records for 3 years and my dr only keeps records for 5 years.  Would I be able to use this with the insurance company to appeal if I need to?  Thanks for any help anyone can give me!  Regina