Hi @Linda Mediano
Thank you for reaching out to Microsoft Q&A forum!
In this article from MS you will find several ways to try to recover your authenticator.
If this isn't possible, go to https://aka.ms/mfasetup to check your verification methods.
Or better still, when you get to the second window, there's an option: I CAN'T USE MY MICROSOFT AUTHENTICATOR APP NOW. In this option you can register a new phone number and Microsoft will call you to confirm your details.
Have a nice day.
Sincerely,