Microsoft Authenticator

Question

Hello, We are a small business. I had to get a new phone number and was not able to modify this info on Microsoft Authenticator. I cannot log in because I cannot get past the sign in that has my old phone number tied to the options (ext or call). I cannot access the security page - no one will return a call at the support ph. numbers provided. At this point, there is no value in suggesting what should have been done. How can we just delete the 2-factor authenticator? Nothing else seems to work and we need access to the emails that we are likely accumulating.

Rachel