I'm on mac too with a win7 vm, I hit upon the idea of tagging them along as far as I could when they asked me to press the windows key and I'm looking at a mac keyboard.

The different shops that have called me all follow a similar set of attacks

1) windows key 2) run command to msconfig 3) browser to download payload.

I had a 'supervisor' on the line once and when they asked me to connect to the internet I'm pretty sure I heard them curse at me with incredulity as I played the 56K dialup sound.

I once got them down a conversation cul-de-sac when I asked them which they preferred - Minesweeper or Solitaire.