Like I said in chat, I think you are trying to enter the wrong password. Even though you know with a 100% certainty that the password you typed is correct, it most likely is not. I know it's not the answer you wanted, but it's probably what happened.
Problem is that players usually start with the wrong password, then enter that same password a million times, and then try to find some outside reasons like account mysteriously deleted, hackers, bugs, etc. Instead they should assume that they are using the wrong password, and should think what other password it could be. This could be a simple case of you mixing two different game account passwords.
For future reference, it's a good idea to have you gaming passwords typed down somewhere in a text file. This way there will be no human error involved.
