cgreenwood: Perhaps we could do a poll then, for those out there looking to switch so they know what they will have to do when leaving?
So far we have:
Whole Month:
Vodafone
Slingshot
Xnet
Pro Rata:
Telecom
Anyone wish to add to the list?
For mobile phone plans, 2degrees do pro rata as well. I ported my number to Telecom when I was half way through my 2degress billing cycle and was (presently) surprised I was only billed on a pro rata basis by 2d.