[EDIT]: Seems the eBay store was linked on the 'official' Mi Australian store website and Xiaomi are selling through a certified distributor called 'Panmi' which is based in Chippendale, Sydney.
According to Techradar, there is an 'official' Xiaomi store on eBay. The store that is selling this item does not have much feedback, but it managed to get on the front page with the 20% sale so although there is some skepticism, I'm assuming it's trustworthy and is the mentioned store in the article.
Not sure if this model is the Global version but the store description says 'Australian Standards certified products with local warranty support'.
If it is really an official store that has local stock and is selling global model, then this is the cheapest I've seen for the Mi Mix 3.
Features:
● Display: 6.39 inch, 1080 x 2340 FHD+ Pixel Screen
● CPU: Qualcomm Snapdragon 845 Octa-core 2.8GHz
● MIUI10 ( Android 9 ), Bluetooth:5.0, GPS, A-GPS, Glonass, Beidou
● Camera: 24.0MP + 2.0MP rear camera + dual 12.0MP front camera
● Networks
FDD-LTE B1 / B2 / B3 / B4 / B5 / B7 / B8 / B12 /B13 / B17 / B18 / B19 / B20 / B25 / B26 / B28 / B29 / B30 / B66
TDD-LTE B34 / B38 / B39 / B40 / B41 (2496MHz - 2690MHz)
https://www.ebay.com.au/itm/Xiaomi-Mi-9-Dual-Sim-6GB-RAM-128…
I will pay $60 more for the Mi 9. SD845->SD855