I've tried everything I can find.
When I attempt to purchase, I am asked for my Microsoft account password, which I put in. Then it asks me to add a new payment method.
1. If I go to PayPal, it opens a PayPal account login in a browser windows. I put in my PayPal credentials, and get this error:
"We are not able to process your payment using your PayPal account at this time. Please return to the recipient's website to complete your transaction using their regular checkout flow."
And that is that. Nothing further can be done.
2. If I go to Credit Card as a payment it asks for my CC payment details, but the Country/Region is locked as "United States" and cannot be changed. There is also a State drop down as well.
Why is the Country/Region field locked?
Further, if I go to my Microsoft Account billing details, it shows "US - Billing Information" near the top, with no option to change it. My Microsoft Account personal info has the correct country set as Canada.