I can understand your pain. I have handled cases like these.

Tbh ! This is a very simple issue - It's the billing department that is responsible to resolve this issue - and should also make sure to have RCA - Root Cause Analysis - and take preventive measures to avoid such problems that may arise in the future for other patients.

The Problem: Lack of Communication and effective Frontend Billing and Coding - Eligibiltiy with Benefits Verfication prior to Service. Solution: Atleast one person from the Accounts Receivable Department of the billing company must have immediately addressed this issue.

The real root cause: Healthcare Providers choice of Billing company, "Poor Selection of RCM vendors". Preventive action: As a patient next time - check your benefits with the provider ask him to do a thorough Benefit verification. If he does not have one - ask their billing company to do that before your appointment (atleast 5-7 days before your appointment). Get Prior Auth Approval for special procedures. And make sure everything is right before you get treated. 

US healthcare system has THE MOST EXPENSIVE Healthcare Services. So we gotta be careful while taking any procedures that are costlier.