Apparently it was due to me not returning the (modem?) genius device. But although it was a frantic weekend of moving house, then family emergencies, I know that I did put the Orcon device into the prepaid traced envelope and into a parcel postage box at my local Post Shop(Paper Plus).
I have since then sent in THREE disputes (latest today) via the online support system under "Bills" and "dispute" However I never received any acknowledgement of Orcon receiving the dispute, never heard back from them, and today got an email saying that my payment was late.
(I did then pay the early termination)
TLDR: How on earth can I go about getting this sorted so I don't get attacked by Baycorp (my brother did) I am not willing to pay $250 for either an Orcon clerical error or NZ Post error!