Help I'm not american but it keeps saying i am so i can't use my Australian card.

just trying to buy State of decay 2. when ever i click buy it comes up how do you want to pay so i click card then it wants me to put in my details but its default set to America so it won't accept my Australian card details. i have looked at my settings
they all say I'm in Australia. i even have a saved card there will all my details. honestly if i could buy this anywhere else i would it shouldn't be this hard to give people money.

:)

 

Changing regions problem

I have just change my region from united states to australia on xbox.com and made sure my billing address was my australian address and cards were my australian cards but when i turn on my xbox 360 it still think my account is american and not australian
and my billing info is my american details and not australian and i cannot add my australian cards. Do i have to wait a certain amount of time before it changes because it change instantly when i first had to switch from australian to united states.

 

credit card

Ok so i am trying to add a new credit card to my payment options and i entered everything in but it keeps saying to enter a valid card number. Im trying to enter an American express card i dont know if that has anything to do with it but ya someone pls
help.