Can't register, says ive already registered? 0_0

[MattoBro]

Okay so I set my name as Matto, have no idea if that affected it but after playing for about 10 minutes it told me to register at the site and gave me my activation code,

I went to the site, entered my name as Matto and put in my code, but then it says tat i've already registered and to log in with my password?I dont remember setting a password at all and i tried using a different name and activation code but it still says the same thing so i cant login someone help please? I really want to play this.