Not able to logon office 365 account or change it

Hello PeterHer007,

Are you the only IT Global Admin, if not then escalate your request to a Global Administrator ? 

The Global Administrator needs to follow these steps:

1. Log in to the Microsoft 365 Admin Center at https://admin.microsoft.com.
2. In the left-hand navigation pane, go to Users > Active users.
3. Find your account in the list and click on it.
4. In the user details pane, click on Manage multi-factor authentication. This will open a new window.
5. In the new window, find your name, and under the Multi-factor auth status column, you will see a link to Disable or Enforce.
6. Even if it says Disabled, the administrator should find the option to manage user settings or reset authentication options. They should select this to wipe your current MFA settings.
7. After the reset, the next time you log in, you will be prompted to set up a new MFA method from scratch, allowing you to register a new phone number or an authenticator app.

If you are the the only Global Administrator, you need to contact Microsoft support directly by calling them.