Using Classic Outlook on Windows for personal email, calendar, and contact management
If the hacker changed the email address on your account, the right tool is the Recover My Account form: https://aka.ms/recovermyaccount. It goes to a specialized team that reviews this type of case.
This guide explains what to enter in each field:
https://support.microsoft.com/account-billing/guidance-notes-for-the-microsoft-account-recovery-form-4dd8fef1-33d2-4fbe-9352-66127ab9b50e
Microsoft says replies can take up to 5 business days. The reply is sent to the contact email you provide, so check its Junk or Spam folder if nothing arrives.
Please avoid submitting the form repeatedly unless you remember new information, since that can slow down the response.
This is a public forum for exchanging information between users, and no one here has access to your account data. Please do not post passwords or verification codes here.