For the phone booth one, get a strong long distance laser and shine it on the back of the prankee's head, ask them to turn around and tell them if your demands are not met, they will be shot. The demand is to drop thier pants or another humiliating task that your saucy mind can think of.
Another idea would be to break out the Samuel L Jackson soundboard and play the phrase "ENGLISH MOTHER FUCKER" when applicable (also "that is some FUCKED up rupuganant shit" is good)
Alternitvely, use an abrasive extremely nerdy archtypal 13 year old hacker voice and ask them where they live and thier credit card number.
Then again, I reckon calling people up and telling them "There ain't no work for you here, boy" or telling them to fuck off you fat cunt will just explode my sides (use they extremly bogan Tasmanian voice for this).
Do what you must to thwart the public's self-confidence patience.