AdventHealth ER review: Grossly inflated charges on my bill for an er visit

I received a collections letter dated 12/22/22 regarding an unpaid bill from 3/10/22 from AdventHealth North Pinellas ER department.

I received a bill for $13,750.09 for less than 4 hours in the ER. (total bill was $19,146.75) The largest part of the bill was for a CT of the chest with contrast... a whopping $9,702.69! A 1 view chest x-ray was $846.88 and an EKG was billed out as $586.48. These are but a few of the charges that I was billed for. I am an x-ray technologist and know full well that nearly $10,000 for a CT is highway robbery.

I researched the Health Care Blue Book and Fair Health pricing tools for similar exams performed in my area... and I looked at the Medicare allowable pricing on the CMS.gov site and discovered the same thing.

A neighbor just shared her bill from the same hospital. A CT scan with contrast was $894. A 1 view chest x-ray was $50. Her entire bill after a month in the critical care unit was $28,357.09. How is this even allowed? How is this fair?

As a side note: I sent Advent a check for $4500 with a notation on the back saying, "Acceptance and negotiation of this check constitutes accord and satisfaction and your waiver of any unpaid balance." I was under the impression that if the check was cashed then they ultimately agreed to waive any balance owed.