I cannot access my o365 admin account in order to change my email settings

Dear sir, madam,

I cannot access my admin page because my authenticator does not generate codes. On my authenticator I cannot login with my admin account. It keeps referring back to the same authenticator. The telephone number it keeps referring to is no longer in use so there seems to be no way to get out of the loop. I can access my work account ([Moderator note: Personally Identifiable Information removed] @calvit.nl).

1. I need help to access my admin page or help to login to my authenticator.
2. I need help to disconnect my external mail account ([Moderator note: Personally Identifiable Information removed] @calvit.nl) hosted by strato.

Kind regards,

[Moderator note: Personally Identifiable Information removed]