Welcome iza s,
I understand how frustrating it can be when your personal Microsoft account may have been compromised, and the attacker may have changed the account's sign-in alias. That would explain why the original email address now returns "That Microsoft account doesn't exist."
Please note that this is a user-to-user support forum. Moderators, contributors including external Microsoft employees cannot directly intervene in Microsoft product features or access back-end systems. Our role is limited to providing technical guidance on reported issues, requests, or ideas.
Please try these next steps (in this order):
1, Sign out of your Microsoft account everywhere, then sign back in only on a trusted device (or a fresh browser profile)
2, Check for connected apps/services that can access your Microsoft account and remove anything you don’t recognize.
3, If you still cannot sign in, complete the Microsoft account recovery form. Gather any proof of ownership, such as:
- Previous passwords
- Security notification emails from Microsoft
- Approximate account creation date
- Purchase history associated with the account (if applicable)
4, If you would like to speak with a Microsoft support agent directly, you can try contacting Microsoft Support through live chat by following these steps:
- Visit the Microsoft Support contact page: Contact - Microsoft Support
- In the search bar provided on the page, type "Account Recovery" and press Enter.
- Click on the "Get Help" button that appears.
- Scroll down the page until you see and click on the "Contact Support" option.
- When prompted to select your product or service, choose "Other Products".
- For the category, choose "Manage Account Security".
- Look for and click on "Chat with a support agent in your web browser".
- When prompted, provide a valid contact email where Microsoft can reach you regarding your case.
- Explain your situation clearly: Be concise but provide all the relevant details.
Thank you for your understanding.