I had the same issue first, that I didn't get an acitvation mail. I changed my email to another email-account, now my account is activated - Unfortunately in the revora forum only.
I have the issue now, that when I try to login to T3A:Online to set the Passwort for playing online, I get the message:
This account has not been activated yet. Please follow the activation link sent to you by e-mail.