Dealing with the IRS is never fun. We'll take our award for "most obvious comment of the day" now.
In all seriousness, despite the agony of dealing with the IRS, you need to go about that interaction in a professional and appropriate manner. Failing to do so can lead to a host of problems for you, and it could mean that you have to pay far more than you should have to. When you are contacted by the IRS -- may it be for an audit or otherwise -- you should consult with an experienced tax attorney if you are confused about how to proceed.
But what if you are contacted by someone who claims to be from the IRS, even though that person is just a scammer? Then it is best to just hang up the phone, or not respond to that letter or e-mail.
According to the Treasury Inspector General for Tax Administration, there have been about 600,000 contacts since October 2013 that relate to scammers purporting to be the IRS. As a result, 4,000 people have lost a collective $20 million to these scammers. Dealing with the IRS may not be fun, but dealing with a scammer can't possibly be better.
Remember to verify any issues that the IRS may bring to you, and don't reveal personal information to people who contact you on the phone or over e-mail. Scammers will make it seem like they are the IRS. Protect yourself and contact the IRS to confirm if the action they are supposedly taking against you is real, and then get a lawyer to protect your rights and interests.
Source: Accounting Today, "IRS Warns of Latest Tax Scams," Michael Cohn, Aug. 6, 2015