Thanks for the post , votes, and comments. We are aware of this limitation and are targeting sometime next year to improve this experience. In the meantime you can sign up for a new account in your desired country and transfer your assets to the new account via Support.
-Azure Billing Teamstu mckenzie commented
My bizspark subscription expires today, but I can't add a new billing subscription simply because I can't add a phone number - my country is not in the list of countries with phones. Why don't you have Seychelles in your phone list, Seychelles (+248)? Unfortunately I can't receive text messages on my Australian phone number here.