Free trial mount a hack?

Hi, at about 1pm server on Korialstrasz on May 10th (Mother's Day) a vast amount of people received a whisper from a toon named BILLING (Note: no blizzard symbol next to their name) saying that there was now a trial mount coming and for people to sign up at [Fake site link removed]. When you visit this site it pops up with the official account name/email --- password page that we have seen a hundred times when trying to log into one's account. Once you enter your info (If this is fake then you are pretty much screwed from this point) you then "log in" to a page that asks you to "verify" your account name and authenticate with one of your secret passwords questions. Once you have done that it changes page to an approval page and says you are approved and you will be contacted shortly. I know all of this since I did it. My question is this: If this is fake what steps can we take to ensure our account is secure?

Things I have done already is:
1. Change my password

Things I need to know how to do:
1. Remove the secret question that was asked of me on that website.