Anesthesia billing says they won't change coding, won't add modifier because I was high risk of cancer and had colon polyps removed? I did not.

All other procedures, codes, appointments, followups etc went through without a hitch. Paid in full. But anesthesia billed for 00840 -- figured it could be an issue. Called, called again, called again, insurance called. Someone finally said "yeah, the bill stands because you're not eligible for modifier 33 due to being a high risk of cancer and having had colon polyps removed in the past"

Except, no TF I have not. Two years ago I had a colonoscopy for as part of a routine check for bowel changes to which the notes say " There was no evidence of colonic or rectal polyps, tumors or AV malformations. The colonic and rectal mucosa revealed no significant abnormalities where visualized. "

Do they just get to argue and say they can charge me more and refuse to code for the sterilization procedure I had because once upon a time I had a colonoscopy? I guess next steps are appeal direct to insurance? Seriously, $52,000 in other charges all paid out perfectly except with this one anesthesia group.