Phone Spear Phishing?

Just got a phone call and it was not on the office phone line, it was on our backup line. The incoming phone number was blocked.

Indian sounding accent. I am from the Microsoft Systems Support, may I speak to the owner of the computer.

Well sir, we have a number of computers here, which one.

The one that belongs to Kathy.

Kathy was also in the office, so I handed her the phone.

Ma'am you have downloaded a malicious file and we need to help you clean it up.

Thank you sir, what do I need to do.

Boot your computer.

It is already running.

OK, do you see the start button?

No, do you mean finder?

Ma'am it looks like a flag and it is on the bottom left side of your screen.

The thing on my computer on the bottom left side of the screen looks like a happy face.

Ma'am you should have a flag shaped icon to start your Windows computer.

But sir, it is a Mac.

Sorry to have troubled you Ma'am; goodbye.

Mike Poor turned me on to this link that shares a lot more information:
https://www.facebook.com/cutsec/posts/436939479729667?comment_id=2674772