> I also needed to pay ¥11,100 of import duties on it - it didn’t seem to matter that the MacBook was mine.

I hate this too.

I've sent quite a few things from one country to another - from myself, to myself. I own the things, I bought them years ago in the country I'm sending them to, took them in luggage when leaving, but am now sending it snail mail back.

They demand I pay import duties, even when I have receipts showing I own it and bought it years ago in the country they want duties.

I've never been able to get out of it, and I've spent hundreds of hours trying.