I recently moved house (after buying a place, instead of renting); and one of the "renovations" I did was to install a prepaid electricity meter. South Africa, it seems is the only country where prepaid electricity has taken off; which I think is a pity. Prepaid utility consumption (be it electricty, water or gas) is easier to manage and offers, in my opinion, far more flexibility than the standard billing methods.
The new prepaid electric meters are also very cool - the utility installs the tamper-resistant meter at the external distribution box (i.e. a straight swap with the old meter) and then provides the user with a remote unit that is used to indicate the value of electricity purchased, usage (accurate to the watt) as well as to buy more electricty etc. The interface unit communicates with the main unit via powerline ethernet - so another cool usage of technology.
As for the confusion - the contractor who installed the prepaid meter, installed it at the wrong house, even though I was given the unit. So, I paid for my neighbour's electricity for a week and the previous owner paid for mine. The guys at the City of Johannesburg offices were stunned at hearing about the mistake - and we all had a good chuckle. Even the contractor couldn't beleive his mistake ... although he blamed it all on his labourer. Personally, I blame them both - the labourer for not being able to do a simple job; and the contractor for not doing his supervision job correctly.