I would regularly get the 'Microsoft' slow computer callers from India.
Sometimes I just tell them I'm on a Mac and they hang up.
Or, if I want a bit of fun I ask them to hold a minute while my call tracker finishes downloading their phone number.
The beginners hang up right away, the smart-a$$es usually say "You can not find our switchboard number", to which I reply, "Country code 91, and area code 33, I then slow down as if waiting for more numbers and slowly say, two, two, (pause), one, (another longer pause) four"...
This is a valid country/area heading for an area in India known for these calls.
And if they haven't hung up, say things like "That's interesting.... my Mac is having trouble with your last numbers, I guess I could just add 3111 for your switchboard?"
Trouble is I'm usually having tea when they ring up....