mattwnz: But why isn't the commerce commission stomping down on this sort of thing if they are only allowed to claim for actual expenses incurred. If it is operated by an overseas company, then all this money being generated this way is stripping NZ of it's wealth.
A question only the CC can answer! Maybe it's something they regard as a trivial matter? Maybe it's something they regard as a legal minefield and they just don't want to go there?
However, I hardly think NZ is being stripped of it's wealth

As for "all this money being generated" - that's really the crux of the matter. We have no idea what that might be without an idea of the number of field operatives PESNZ has. We could make all sorts of questionable estimates though...
It'd be nice to see some information around the extent (operating costs vs operational income) of PESNZ but I'd suggest "commercial sensitivity" would prevail. This is why I believe that, when challenged, they're more likely to waive a fine than try and actually prove the value of their claimed loss.
mattwnz: Maybe the commerce commission don't received enough complaints about it, and as it is am amount that people think, I'll just pay it to be rid of it, many people probably can't be bothered spending their time. eg $65 vs 1-2 hours of time.
You're quite likely right, the amount isn't high enough for many people to pursue the matter with any vigour.
I spent probably 15 minutes writing my letter (which I can't find unfortunately, written mid 2010) but probably a quicker way of doing things would be to lodge a dispute through the appeals section of their website. After filling in all the necessary details, concise wording along the lines of the below should suffice:
I am hereby disputing this charge. What you are seeking is called "liquidated damages" which pertains to an actual loss arising from a breach of contract. This is not something you are legally entitled to profit from. Please provide me with evidence of your loss to the amount claimed or of your wish to have this matter proceed to the disputes tribunal.
Then take a screen dump before hitting the send button as you probably won't get a confirmation email which quotes your comment.