For the life of me, I can’t seem to update my delivery address at the online shop check out.

My details (including my address) are complete and correct in my Sonos profile, but when I try to complete an online purchase, my details don’t pre-populate at checkout and the delivery address is stuck on USA.  I click the button next to “country” but there are no other country options except for the USA - which doesn’t particularly help me since I live in Australia…  

Any ideas why this could be?