You could not log in because the service account in question is not registered.

[Ed_N_Ants]

I think, either you registered the code to the wrong account, OR, Square Enix lost your registration and decided to pocket the money you paid them. Since SE has not been shy about flouting its complete and utter ineptitude as well as indifference to customers, it's probably the latter.

Try the registered to wrong account form I guess.

I've seen some other people with this issue and everytime that I see it they have put in the incorrect code... I have heard that the d's look like 0's and you need to verify you have the correct code... Once you put in the correct code it should give you a confirmation code and show you and active..