If you are already registered, you should not re-register, as this would result in duplicate accounts and unnecessary mess.
I have just tried to login, and everything looks fine. Try to login using another browser, as SDL website does not work correctly with some browsers.
I do not try to register again, but once I enter my credentials on the login page I am referred to another page "Complete Registration", which contains all my data and VAT number. When I try to confirm I get the error message that my VAT is not valid and that I should try again.
So there is no way to even get into the account.