Hi AmblyoMoron,
Please be advised that as a community advisor, I don't have access to your personal account to check details in the backend. this is a Microsoft public peer-to-peer forum. I'm a fellow community advisor(not Microsoft) to help other community members with their issue.
Now to look further into this issue.
You mentioned that you could access your Windows computer, you could access your account. To check your email address on windows, go to Chat, start a chat and over on the Profile Pic beside chat message.
Let me know if you see a different email address.
I'm not sure if there has been any change to your email address from the Users in Azure AD. If you have access to your admin account, the one you used to sign up for MS Teams free organization:
Go to https://portal.azure.com > Azure Active Directory > Users > Search for your name, click on it and check the email address property.
Regards
Nik