How could I get access back to my email?

Guys, I am screwed! To reduce junk email in my [Live.com] account (which is my primary email for everything, including my Microsoft 365 subscription, login to my computer), I followed Microsoft's advice on its forum and made my secondary [Gmail.com] address my primary alias to log in to my [Live.com] account. I saw an immediate improvement, and the amount of junk email dropped significantly. I hadn't had any issues sending or receiving email with [Live.com], and logging in with [Gmail.com] was perfectly fine until yesterday (October 4) evening.

Yesterday afternoon, October 4, as an extra precaution, I selected "Sign out everywhere" in my [Live.com] email settings. I logged back in on the browser's Outlook Web App using my [Gmail.com] alias and tried logging in with my phone number as well, and everything was fine. After two hours I got the first pop-up message on my iPad's Outlook, Defender, and Reminder app to log back in. I tried to log in with my [Gmail.com] address, which had worked a short while ago, but I got the following error message (at the bottom of the message), which means my [Live.com] email no longer exists; even after I reached out to Microsoft support, they couldn't find my [Live.com] email anywhere in their system! It's just vanished!!

Even my correct password showed as incorrect when I tried to verify my information as the error message asked, and it keeps saying my password is incorrect. According to the Microsoft support engineer, I tried to reset my password using the code sent to my [Gmail.com] email and my phone, but after I entered the code from Microsoft, it kept showing a system error message, and the Microsoft-given code didn't work.

After spending over two hours with the Microsoft engineer and giving him access to my laptop, I didn't get a resolution. Therefore, once I requested to escalate it to the next level, I was provided an online form named 'account-reinstatement '. I submitted that form with all details last night.

I had a sleepless night; I am scared, and I am anxious. I followed the Microsoft email settings, didn't hit any delete button, didn't get any warning message, just clicked "Sign out everywhere" and now I can't sign in or access my two-decade-old primary Live.com email. I can't even access Microsoft Office applications or OneDrive, as I said that [Live.com] email is the primary email for my Microsoft 365 subscription.

Error Message: "The inbox you've been using is no longer available. This can occur when your account is owned by an organization, or when someone else confirms ownership of the email address.*

You haven't lost access to the other services you use with your Microsoft account. However, you must choose a new primary alias to continue."