Did not pay account for procedu that they approved

On July 1st my son went in for a quick procedure that was pre approved by Discovery. When the account arrived they said they can`t pay as the procedure is not covered by them due to an infertility procedure. My son is 16 and had pain caused by a vein that had to be sorted. I have been with Discovery for almost 9 years, and have had no problems. I will be cancelling my membership as soon as I can. The doctor is willing to provide a letter that the procedure had nothing to do with infertility.