A couple of things....

What diagnosis code did they use for the second mammogram? The coding would be different from an annual screening mammogram. Didn't the Radiologist recommend follow up with your regular Physician? Did you go to your PCP or Gyn for a breast exam to confirm the location of the lump and documentation on your medical record? That could be part of the problem, as well.

Are you sure diagnostic (not screening) mammograms are covered by your particular policy?