Ok where to start on this one, well first of all don't use the YouShop service if you know you will be over the gst threshold, why? Well NZ Posts YouShop service has as of the 1/12/17 changed the way they work, as of that date they are no longer a Postal service for delivery of youshop parcels but are now a Freight forwarding company, what does this mean, well quite a bit actually, they have started up a company called Sendit which is NZ posts own custom brokers, so what happens now is you get an email from sendit (with the notice number of your goods) requesting an invoice for the goods they are holding for clearance
(invoice= Proof of purchase ) so what is happening now is they will no longer give the value amount to nz customs like they used to ( they already know the amount because you had to put this in on the YouShop website before they will even ship) untill you send them the "invoice " they are offering to do this for you at a cost of $46 or you can use any other custom brokers at considerable cost.
so this means you cannot get the Entry number to make payment to NZ customs for release of your parcels.
I've spent the last 15 days trying to get my parcels released and I can say the whole thing is a total fiasco!! It was so simple before the changes that it's obvious they no longer want to keep youshop open, I'll be using shipito in the future.