866-864-5678

I received a call but did not answer because I did not recognize the number.  I called back and got a message claiming it was the IRS

I had the same thing exact ame message

I got the call saying they were trying to collect a debt from me from the IRS.  I heard that the IRS doesn't contact you by phone and wouldn't resort to a collection agency.  When I tried to call them back, I was put on hold forever until I just hung up.

Read my post.  Same thing.  It was from American Agencies.  If you google that agency you will see a lot of stuff on them and how to handle it again if they call or if they put anything negative on your credit report.