Do not answer calls you don't know and never call them back. The IRS will not call you. The IRS won't ask you to pay in i-Tunes cards. The IRS will not wish you "good luck as the situation unfolds". Trust yourself and your instincts - do not let a bully intimidate you by threats that are nothing but hot air. This is a SCAM. Do not call them back.
Received continuous bogus messages from an unknown source at this phone number regarding a "case". Left this number on voicemail. I never called the number back