Local hospital debt collection

Claimed to be from co named "Mandatory Arbitration", with callback 888-753-9414. Supposed to be returned item from bank & had to respond w/in 48 hrs to avoid "finalization with county". NO VALID BASIS. If not a sleazy debt collection co, it sure imitates one.

I got 2 of these on my voicemail Friday.Said he was John Spencer and I had 48 hrs to call back or my case would be sent to the county. Well guess I missed the deadline. No idea what this nonsense is about. Don't owe anybody anything

Got several of these calls from "John Spencer" I called them back several times at 888-278-8565 no answer, got several more voice mails from "John Spencer" called them back at 210-787-1736 spoke with and "Anthony Davis" he claimed he had no record of me or the case # that was left on his messages he claimed I never got a  Phone from his Company and hung up on me. (he was right I had 5 phone calls) I called him back he answered and hung up on me again.
So, I called him back again, he had a girl answer and tell me they took my # out of their system and she hung up on me.
Anybody have an address for these people?