Left automated message seemingly cut off at the beginning to call for more information about this case file and to please call immediately on department number. I was concerned it was regarding mis-use of a credit card number so called back. Person claimed to be with IRS and that there were charges against me, that I should have received a letter confirming the same. They had an address they tried to validate but it was not accurate.
Called me three times in the scope of a single morning with the same automated message about an alleged IRS lawsuit. FYI the IRS will never alert you of action by phone (they send notices in the mail), and will certainly never file a lawsuit against an individual without attempting to resolve issues or collect through other means first.
This is a scam call designed to scare people into thinking they owe tax they don't actually owe and pay it to a party that isn't really the IRS. Block and move on.