There are loads of messages like that circulating.
From exaclty what adress did you get the mail? Check the adress for @....
Alot of people inpersonate Blizzard with "[email protected]" and such, If the adress is not "[email protected]" you can just ignore the mail.
If the adress is indeed "[email protected]" for example, then look in the mail. If they ask you to reply to another email in the mail, its probably gonna be a "...@hotmail" or something. Just ignore that aswell. Someone has probably sent a fake email that you cannot answer to, cause the adress is fake, so you are directed to another "not blizzard" email.
If there is nothing like that , if the adress is a Blizzard andress and no faked email is linked in the message, an email where you should send the info, I dont know what to do. Chances are that it's actually Blizzard and you might be ****d.