My solution:
when they ask for me by name I say "Oh you need to speak to my Dad, I'll just get him..."

Then I place the phone on the stairs/side etc and shout "Dad!" loudly and leave it there for 5 mins before hanging up.

I've also discovered when they start out with "Hi I'm sharon from FuckwitsRus, I'm just calling..." I interrupt and ask, "sorry which company was that? Just need to write it down..." they normally hang up on me then.
(golddust QOTW now revolves around being a cunt, Fri 2 May 2008, 11:06, Reply)