Account hacked

Use the official recovery and support paths for an account takeover where the sign-in alias was changed.

1. Start with the hacked-account recovery flow and enter the original email address or phone number. The tool can provide self-help steps or an option to talk to an agent: Start
2. If the username is no longer recognized, use the username/password stopped working flow: Recover your account
3. If it still says “We couldn't find an account with that username”, use Contact support from that page and state that the username stopped working after an unauthorized alias change: Contact support
4. Contact Microsoft Support through the public support entry point if needed: Contact Microsoft Support. Enter the problem, select Get Help, then Contact Support.

Important points:

• Support agents cannot send password reset links or directly access and change account details.
• Keep the Microsoft security emails and prior account details ready, but share them only through a private support channel.
• Before changing any passwords, run a full malware scan on the affected PC. In Windows Security, open Virus and threat protection > Scan options > Full scan > Scan now.
• If the same password was used anywhere else, secure those other accounts as well.

References:

• My username and password have stopped working
• How to recover a hacked or compromised Microsoft account
• What happens if there's an unusual sign-in to your account
• Microsoft account compromised: primary alias changed and original email no longer recognized - Microsoft Q&A My personal Microsoft account appears to have been compromised within the last 2 hours.