Managing personal Outlook.com account settings, security, and privacy
The email address and the recovery phone number are actually part of the security info.
Unfortunately, there is nothing that can be done once the security info has been modified by the hacker.
Please be advised that Microsoft Support will not be able to assist you with manual recovery, unblock, and escalation for this case, as stated in this article, that they are not permitted to send password resets, access, or even change any details on the account:
Moving forward, please check this link for more information on how to secure your account and to prevent hacking incidents:
https://support.microsoft.com/accounts-billing/manage/how-to-help-keep-your-microsoft-account-secure
Best regards,
Darhyl