Dear valued customer,Recently we have received lots of complaints about locked account during powerleveling. We are sure that it is because recently Blizzard inspects the account logined with different IP address so strictly that your account will be locked.
We find that changing the password can largely reduce the risk of locking. So please go to battle.net to change your password, and please do not login your account on battle.net or in game. Since Blizzard will continue to lock your login IP address. You also can contact our customer service to make sure if your password is valid.