I also got the call with the same message regarding, " the IRS is suing me....!" the call was from Algonquin, IL and they did not answer; The message I then received was that the cell phone I was calling was busy at this time.  Since when did the IRS start calling with automated messages from a cell phone in IL?  100% scammers - don't waste your time calling them back unless you want to have fun with them and waste their time.