Confused about my denial

Ok So I have been denied. I got my letter today from insurance and all it did was repeat there policies. It gave no info on why I was actually denied.  I called and was told that they can not tell me why and I will have to get the Dr's office to call to find out. What crap! Does this sound right? I mean why would they not tell me? I havr Tricare if any one has any insight. I of course want to appeal but I have to know why I was denied first... frustrating.

Tricare is weird, you have to be over 100lbs according the the Metlife Weight and Height chart and they do not budge on it that could be a reason, or the dr. may have given incorrect height and weight many things call them Monday