My account was compromised

If the primary @outlook.com alias was deleted by the attacker, that address can become permanently unavailable and cannot be recreated or attached to another Microsoft account. That matches the symptoms described: recovery says the account is not available, and mail sent to the old address returns account unavailable.

The supported recovery path is:

1. Use the Microsoft account Sign-in Helper first. It can guide to the correct self-help path or offer the chance to talk to an agent.
2. If the account still cannot be recovered, use the Microsoft account recovery form and provide as much verified historical information as possible.
3. If two-step verification was turned on and none of the alternate verification methods are accessible, support agents cannot reset the account, send password reset links, or change account details.
4. If access is regained, immediately:
   • run a full malware scan on the PC from Windows Security → Virus and threat protection → Scan options → Full scan → Scan now
   • change or reset the password
   • review connected accounts, forwarding, and automatic replies

For OneDrive access, if the Microsoft account itself is blocked or unavailable, the account status can be checked on the Microsoft services account reset page. If the block was triggered after recent verification by text message or large file sharing, the block can be removed within 24 hours.

A key limitation in this scenario is that Microsoft support does not manually recover the account by changing security details on behalf of the account owner.

• How to recover a hacked or compromised Microsoft account
• Help with the Microsoft account recovery form
• What happens if there's an unusual sign-in to your account
• Reactivate an account that has been blocked
• My outlook account has been hacked and I am unable to sign in - Microsoft Q&A