TOTAL SCAM! Don't call these people back! I received a call at my office (which is a law firm) from a Brian Jackson or Johnson. It was a man with a very thick middle eastern accent saying I needed to call him back immediately and he referenced an IRS debt which does not exist. He threatened that if I did not call him back that I would be "arrested" and a "case" had been filed against me. I work as a paralegal so I knew it was total B.S. but I'm sure these con-artists  have probably scammed plenty of hardworking people out of their money. Ignore them and report them to the Treasury Inspector General at the link below!

http://www.treasury.gov/tigta/contact_report_scam.shtml