Hello there, sad to hear about the issue you are dealing with, but I don't handle the transactions on this site so I cannot help you here, you can contact itch.io support (they have their email linked somewhere in "help" or "support" tab) and tell them about the issue or you can look for solution online in the forums here.
By the way, people in Brazil can still buy itch.io games with credit cards or PayPal, you only can't pay directly in Brazilian Real, this is the answer I got while looking online.