I sold a pendant to a girl before Christmas. I live in New Zealand, she lives in Canada. The pendant was shipped out on the 6th of December. On the 23rd, I had a big tidy-up in my room and threw out the shipping receipt from New Zealand Post thinking that it must have arrived, as I've never before shipped something overseas and had it take more than two weeks (stupid, I know - I'll never again throw out a shipping receipt until I have confirmation of the package's arrival at its destination). On the 24th, the person I sold it to emailed me asking when I'd shipped it out, as it still hasn't arrived.
My question is: Which shipping company will this be a problem with? I remember reading a few posts a week or two back about Canada Post being completely overwhelmed and taking up to a month to deliver parcels. However, I don't want to blame Canada Post in my reply emails to my customer if it's actually a fault with New Zealand Post. In past experience, New Zealand Post has been pretty good at delivering parcels overseas promptly, but I usually ship to the US or UK, not Canada.
(I told her I'd refund the money if it hadn't arrived by this week, so hopefully I can avoid bad selling service on my part.)
Edit: Apparently it has arrived, so thankfully I don't have to refund the money. Thank you all for your advice!