I've been getting a once daily call from these idiots. Area code is from Michigan. If you call back, it's always busy. The caller claims to be from "Windows" and says that your computer is sending error messages to their offices. If someone were to call from "Windows", they'd be calling from Microsoft, first of all. Second, Microsoft wouldn't call. Third, I tell them they're not who they say they are and, after assuring me they're legit (for a minute or so), they hang up. I laugh. Don't give them any info. They will try and steal info from your computer, more than likely.
Called my number this evening in BC - didn't answer as didn't recognize the number. No message left, so now that number is blocked. If someone doesn't leave a message, I always block that number, if I don't recognize it.