Managing personal Outlook.com account settings, security, and privacy
Hi,
It appears that the hacker has successfully changed your email address and taken over your account. Honestly, based on my personal experience, it can be very difficult to recover an account after this happens, and it may be permanently lost. You can check the Microsoft article below to see if the recovery steps can help:
If none of the steps work, I’m sorry to say that since the username has already been changed to a different one, recovery may no longer be possible, and the account may unfortunately be lost.