Finally contacted Blizzard because of the emails.
Apparently only way to unlock my account is to send them all data about the account, TOGETHER WITH THE ANSWER I FORGOT, or send them a scan of ID or Passport. Would be fine if not the fact that this Battle.net account didn’t have my real surname… Meaning that there is just no way for me to get it back, and with it to stop getting those damn emails. Seems I will have to add Blizzard to spam filter…