Hello Angel,
Thank you for posting to the Microsoft Community.
I understand that you are having trouble accessing your email after changing your phone. May I please verify the type of account you are using? Is it an M365 work/school account or a Microsoft/personal account like Hotmail/outlook.com?
In the meantime, since you posted in the education category and if you are using a school account, you may need to contact your school's M365/IT administrator to reset MFA for you through the Azure admin portal. In the Azure portal, the administrator can set their account to Require new MFA registration. In the Azure portal, the administrator can set your account to Require new MFA registration. This disables all previous authentication methods, removes the phone and you will then be prompted to configure a new MFA authentication method the next time you sign in so that you can do the set up afresh.
The admin can also add another authentication method for you like phone/SMS in this portal such that you have more than one option. Manage authentication methods for Azure AD Multi-Factor Authentication - Microsoft Sign In | Learn with Microsoft
For guidance on how to find your admin, please refer to How do I find my Microsoft 365 admin? - Microsoft Support
If your account is Microsoft personal account (outlook.com/live.com/Hotmail.com), please reply back to us, so we can involve personal account team for further assistance.
Thank you for your kind understanding and have a great day.
Best regards,
Ashraf.