Need help recovering Xbox Live Account (Sea of Thieves related)

Hello!

I really need some assistance please!

I've been playing Sea of Thieves on Steam for a couple of years now and I've always used the same email for my xbox live account. Recently, I've had to take my computer to repairs and ended up with having to get my windows reset/reinstalled due to some issues. When I got it back, I reinstalled the game. But for some reason, instead of steam linking to my xbox account, it made me create a new one with the same email. My old account still exists, but I can't seem to connect with it anymore. My new account shows every time I log in.

I've already tried calling Xbox Support, but the guy was useless. He told me that my email was no longer connected to my old account and that he couldn't help me without an email. He basically told me that it was lost.

I hope this isn't too confusing, but can anyone help me? I have two years of Sea of Thieves achievements in that old account and I really don't want to lose it.

:)