Why are you calling? This scam is too common. IRS DOES NOT CONTACT BY PHONE! They send out a letter with complete details $$$ amounts and reasons for their inquiry.
Fake IRS scam, same as above. IRS doesn't leave low-quality electronic-voice messages, they send mail. I have a few calls at work from them, I never bothered to answer.
Two messages both from IRS stated the officers name and that I had to return the call immediately and I called back before I checked the number got no answer looked up number figured out it is a scam...