linw: Looks like you are in a bind but, wow, what expensive 'postage'.
Just thinking, if the goods were dutiable under Canadian regs, how come they were effectively not dutiable if sent by courier?
Normal post doesn't have the same import checks and the documentation is different. As a new settler I had to submit a full inventory of goods I was bringing in on arrival and another for goods to follow. This inventory, which is very detailed, is processed by customs and the are granted duty and tax free status. In Canada, everything valued $60 and over is subject to duty and taxes. With courier documentation, I included the paperwork to show that the goods contained in the boxes matched ones listed with approved duty/tax free status. The courier checks them through customs and off they go.
However, with standard post, the documentation is not provided, the file number (which was written on the outside of the box too, if they cared to look) is not checked in their computer system, and duty is assessed based on what contents are listed in the little sticker NZ Post puts on the box.
It all comes down to how imports are handled - couriers do it directly with customs, post does it with customs officers in the mail handling facility. Two different processes with two different sets of paperwork and two different outcomes. Customs had told me not to send by post because this happens, that shipping, courier, and carrying are the three methods by which to avoid problems.
I paid to avoid these problems and didn't get what I paid for. The boxes have now been picked up, CAD$600 paid, and I now have to go through the process of initiating a review to claim back the duty. What fun :-(