Your currency will not get automatically updated if you change your billing address. You will need to reach out to support to have this manually updated.
The currency is determined according to the billing address you had added upon first sign up.
For example, if you sign up in the US with a US credit card, then later move to Canada and update your billing address and card to be Canadian, the Canadian card will still be charged in USD unless you reach out and request us to switch the currency.
Search the Help Center to find answers or, if you're still having trouble, email firstname.lastname@example.org.