Minecraft Feedback Website, Minecraft Dungeons Launcher and Minecraft Windows 10 Login Issue

(No specified version as this is not a Minecraft game version issue)

Whenever I log in to the Minecraft Feedback website, Minecraft Dungeons launcher, minecraft.net website and when I play Minecraft Windows 10 Edition (I have only tried logging in on those so far) with my Microsoft account login details, it logs me into a different account with a different username. It is supposed to log me into my account with the username "Mania NATION" and all my details and posts and such, but instead the username is "AliveMarlin1732" that had no posts and no information. This affects with the feedback site as everything I post is now under a different account and I cannot view my posts or login from the "Mania NATION" account anymore. I can assure you that i have 100% logged into the correct Microsoft account and have definitely used the exact same login details that i use to login to the Microsoft account itself on the Microsoft website.

It also affects Minecraft Dungeons as when I logged into the Minecraft Dungeons launcher, i realised i must have purchased the game on the "AliveMarlin1732" account and not have known. That REALLY affects it as if i can't login to the correct account and play the game because it may have been bought for a different account but it wasn't my fault and it's really annoying. I do not want to have to buy it again just because of this issue logging in. I bought Minecraft Dungeons on the minecraft.net website and not the Microsoft store, and I bought Minecraft Windows 10 Edition in the Microsoft Store (which is logged in to my "Mania NATION" account).

I'm also afraid when Account Migration comes out, that it may affect it in some way and i am really trying to find help for this issue quickly so as to not lose my whole account because of this login issue.

Before coming here, i contacted Microsoft, but they assured me the account and username logged in as my "Mania NATION" account and the problem is on Mojang's end. I've also contacted Mojang support on Twitter and via a support ticket, but they could not help and only told me to report it here as a bug. Microsoft also told me that this username and account is an automated account or something like that, that was automatically created upon logging in. 

What I expected to happen was...:
It would log me into the correct account with my "Mania NATION" username,  correct account details etc. 

What actually happened was...:
It logged me into an account with the username "AliveMarlin1732".

Steps to Reproduce:
1. Login to the Minecraft Launcher and Feedback website or Minecraft Windows 10 Version with my Microsoft login details
2. Check the username on Minecraft Dungeons launcher and go to My Profile on the Minecraft Feedback website and check username and account details there as well. Also, check the username under my Minecraft Windows 10.