I would recommend removing the Microsoft account all together and stop using their services completely. https://support.microsoft.com/en-us/account-billing/how-to-close-your-microsoft-account-c1b2d13f-4de6-6e1b-4a31-d9d668849979
I for instance have had only one business account the whole time with the same email address and only one alias, still I get two options when signing in, Microsoft claiming I have both a personal account and a organisational account.
I can sign into the "personal account" with the authenticator code but not for the "organisation account". The sign-in page never gives any option to use another method.
The authenticator code only work for the "personal account", which I never had btw, but not for the "organisation account".
This way I can not access the admin area or contact support because even-tough I can login on the "Contact us" page with my "personal account" it requires me to login again to my "organisation account", something I can not do since the authenticator code does not work.
The Microsoft developers must be proud that they can create endless feedback loops that throws business customers under the bus.