Same here. I called the number back and they are a 3rd party billing company. It was not for collections (although they might also have a collection faction). This company handles the billing for several small health clinics.

I got a call from the same number has a little of an acent .left a message with a return number. could quite make out phone number he left to call back I only was able to make out the last 4 numbers. sounded like he mumble the first part. It might be a collection agency.

This number called me and left me a voice mail that said it was very important that I call back. Didn't leave a company name or why it was so important.