Can not access Microsoft Authenticator

Question

Recently had some personnel change at my business and the leaving party had set up our Outlook email. The Authenticator app was set up through their personal phone and we are unable to switch or update the MFA device. I still have access to the email through the office computer, but I am unable to edit any account information without MFA access. Microsoft doesn't seem to have a way to contact anybody regarding this issue. Any support at all is appreciated.