My favourite answer to a telesales person was from some American radio show - it involved some guy who sounded like Tommy Lee Jones in No Country... answering with some background noise sounding like police activity, suggesting that if the caller knew the murdered person they were trying to call they needed to give evidence right now - what's your name, where are you etc etc. The protests of 'I was only trying to sell him something' were unheeded to comic effect, as the details of the deceased's chalk outlining etc unfolded in the background. Can't find the link sadly - love to have the nads to try it, but maybe leave that one to the pros.