I got a call from that number, they left a voice mail. They tell me the MicroSoft Windows license key on my Mac (running OS 10.14.2) has expired and it is essential that I call them to get it renewed.
A couple of questions:
What is a license key?
How did they know I'm running the secret Windows version of 10.14.2 on my Mac?
Should I call them to see what line of BS they're going to give me?