Hi there! Sorry to hear about what happened. Based on what you've described, it sounds like you may have entered a Microsoft verification code on a phishing site, allowing someone to take over your account and change its associated information such as deleting it.
Please start with Microsoft's hacked account recovery guide. If your account was closed or deleted, recovery may depend on its current status, so follow the instructions provided by Microsoft page.
Once you've recovered access, secure your account and review its recent sign-in activity.
For the future, never enter your Microsoft verification code on an unfamiliar server or website, click suspicious links, or share an OTP with anyone. I hope the Microsoft guide for hacked account helps you recover it!