Ooops also meant to add to that post that CX were using Gogo 2Ku as their WiFi solution on their 777 fleet. Air NZ use Inmarsat GX which is Ka.
It is a totally different platform and hardware and presumably Air NZ have decided that the cost to support a one off plane is simply not worth it - they certainly wouldn't be paying anywhere near what they do for the GX solution which is a fixed cost per aircraft for a set bandwidth.