Railyard Urgent Care

I've been to this place several times. The care is okay - there's a PA/RN named Mark who is particularly good (not sure if he's still there). HOWEVER... my last time there I paid my deductible as usual, then got a bill for $80 about 4-5 weeks later. My insurance had covered these bills in the past, and so I sent it on to them. Never heard back from my insurance. Or from Railyard Urgent Care. Then about 4 months later I get a notice from a credit score tracking service that there's a collections ding on my credit score that's dropped my score SIXTY POINTS. There's no contact info on the credit score notice for who's complaining about this mystery debt. So I wonder about this for a few days, then decided to call Railyard Urgent Care... just to see. Sure enough - they've got an unpaid bill for me that they've forwarded "to our collections department". They've also got the wrong address for me, though I've been getting forwarded mail from other companies to my new address for months. They sent one bill, and then went directly to collections. Thank God I don't need a decent credit score for anything right now, but it's unclear how long this ding will stay on my report and how much harm it might still cause. I am never going back to this place. They do more harm than good.