It is a fake IRS phishing scam. If they quote the last 4 digits of your social security number ask for their IRS badge number and tell them you have to call them back. The IRS does not call from untraceable numbers and if you owed money like they claim they would send you a letter first not an automated call. DO NOT GIVE THEM ANY PERSONAL INFORMATION.
Hello, I got a call saying I owe the IRS $75,000. They went all the way back from 2010. They threatened me saying I would be arrested because I was using fraudulent tax return. They were foreigners. The guy gave me the name, Daniel Johnson. ID: Irm1123 He said my case number was CP10173t. They asked for my date of birth and the last 4 of my Social and asked that I repeat my Address. Not knowing any better, I went on and gave it to them. Didn't think about it until after the call. If the IRS were looking for me, they would already have all of my information and they wouldn't call they would send a notice in the mail.