They got to the point here that it wasn't amusing any more. When the next thick Indian accented female started the "Microsoft Department" spiel, I told her to stop wasting my time and hers, and hung up. She rang back and gave me a tirade of insults, including some very imaginative ones. I just hung up again. She didn't call back.
My wife has had a few when I've not been around. She asks them how it can be, since she doesn't have a computer.
I've also done the "I can't find that screen on my Apple Mac" thing. That prompts an instant hang-up at their end.
It's useful that Milo's found one of the outfits doing this. I suspect there will be more than one, though.