Richard, it is NOT the IRS. If the IRS had filed a lawsuit against you, you would know about it because you would have been served papers. Whoever is calling us from the number 312-458-5721 is only trying to scam you out of money. If you want to do something, go to the website of your State Att. General's office and file a complaint with them.
Got 5 voicemails from the number today telling me a lawsuit was filed against me and to call them back for a case file. Number shows up on ID as wireless caller...