Received the same phone call/voice mail from Nikki Johnson. Looked up this number because I knew the message didn't sounded like a straight up scam. So glad I had looked the number up. Thanks for all the warnings!
Just received an automated call a few minutes ago from this number but figured if it was the IRS they would send me a letter. The call stated it's important that I not ignore the call and contact them asap. Next course of action for me was to look the number up. I've just blocked it. Thanks everyone for sharing your experience.