I get confused about this process too, but here's what I would do.
Write a check for $167.00 and on the back write "For deposit only for Emergency Physicians LLC" or whatever the OC's name is, make copies of it front and back, and and send it ASAP with a letter stating the account and that it is payment in full. I doubt they won't cash it. Then THEY will have to pay the CA.
CAs really only want to report to make you pay, and if they have been paid, they don't report.
If you do this right now, before it hits your CR, and it DOES hit your CR, then you have copies of your cashed check, or money order and can prove it was paid before it was reported. Then you can start with the HIPAA process. If a debt is paid, it can't be validated, right?