If you need to get rid of a nest you need some sort of wide, flattish implement (a squash or tennis racket should do the trick and a spade works quite well apparently). You then need to hit the bottom of the nest quite hard with a single blow. Apparently, because of the wasp's physiology, this will stun all the wasps in the nest simultaneously whereupon you can just drop the nest into a bucket of water and drown them.
Saves on any of these expensive pest control companies and /or nasty insecticides.