There is a known bug or issue, that has been covered in the update and survey announcements a while ago, and that when you get asked to confirm your pre-order it looks like it’s asking you to pay a second time. There will either be a credit showing you can apply at check out to cover the cost (it may not be obvious initially), or if not when you pay just email [email protected] and they will immediately sort it for you and refund second payment, etc…
@plamen should be able to confirm that’s still the case.