That became a bit unstuck. What I found was that Telecom sold the Tivo's through a separate company which no longer exists.
I know you have probably put this behind you, but when I purchased mine, I purchased it directly from Telecom and it was on my bill from them. So intrigued who the separate company was.
As per the other thread on this at the moment, it does look like they can now be modded, which is another possible solution for some, but potentially pricey.
I only mention this because there is a technology lesson here. Just because you paid on your telecom bill is not proof of purchase between you and the seller. If you delve more deeply you will find on your original contract that the supplier is actually "XYZ Ltd" Not "Telecom Ltd".( I purchased directly off telecom as well - or so I thought)
If you were to audit the money trail your cash leaves your bank account, enters Telecoms bank account and then heads off to XYZ Ltds bank account. I 'd argue there is some deceptive selling happening there - but as you say its kinda behind me.
But my advice would be when making a purchase look very closely, not only at the conditions of sale but also who the seller legally is - that's the person you will pursue in a CGA claim.
I haven't bought anything from Spark or Vodafone for while. If you have go have a look at your purchase contract and see who actually sold you your device.