I found this from blizzard support.
"We temporarily lock Battle.net accounts when there’s a change in access. This can mean a long time has gone by since last time you logged in, or maybe you’ve logged in from an unfamiliar location.
We’ve sent you an email with a link to reset your password, which will unlock your account. You can also recover access to your account on our Can’t Log In page. If you don’t have access to your email address or can’t recover your account, contact us.
Battle.net Phone Notifications makes it easy to recover your account if this happens in the future. Simply enter the code sent to your mobile phone to unlock your account."
Try the “can’t log in” page as instructed. That’s all i can say on the matter.
I hope it works.