Claim for required bowl prep denied

I confirmed with your representative on 5/12/2021 that Suprep was covered if I submitted a claim with my receipt to my medical plan, not the prescription plan.  I have his name and case number and the call is recorded.   Bcbstx denied it and has refused to reimburse me.  I have spent weeks arguing with BCBSTX Escalations department and now have filed a complaint through my employer.   Federal law states there should be no out of pocket costs for preventative procedures.   Explain why you are refusing to reimburse me?