You are correct in your assumption here and the account is currently secured by us. You will need to reach out us using the “I’m hacked” or “I can’t log in” options on the Support site, and you can reach us through a ticket for the Support Team to recover the account to you.
This link should take you straight there: https://eu.battle.net/support/en/help/product/services/316/973/solution
Click on the Contact Us, then put in your original account email that you used to log in. You should be contacted within 24 hours usually once you’ve sent this ticket to us.