I too got the call three times. Clark Howard reports the IRS only makes notifications via US mail, NEVER by phone. So I circle filed the message they left me.
Have received 3 calls from this # in the last 4 hours. Leaves VM saying it is the IRS and that a law suit has been filed. Called the # back, rang numerous times, no answer. I too, have been told that the IRS will not contact by phone only by USPS. Also, my phone indicates it is a wireless caller out of Georgia. Wish there was something that can be done to stop their calls...