A cloud-based identity and access management service for securing user authentication and resource access
Could you please confirm whether this issue started after changing or replacing your device?
If so, you could try accessing MFA from the old device to see if the Microsoft Authenticator app is still working there.
In addition, if there is another administrator in the tenant, you could ask them to revoke or reset the MFA methods associated with your account.
You can refer via: Manage user authentication methods for Microsoft Entra multifactor authentication
If the above options do not help and there are no other administrators in the tenant, the official path to regain access is to contact Microsoft Support by phone for tenant recovery assistance.
Since you mentioned that Microsoft Support has not responded for the past two days, could you confirm whether you have already tried contacting Microsoft through the regional support phone number, or whether you have been able to reach the Data Protection Team and currently have an active tenant recovery case with Microsoft?
If you have not yet contacted Microsoft by phone, I would recommend doing so, as it is often the fastest way to escalate tenant lockout scenarios. You can find the support phone number for your region here: Contact Microsoft Support
When calling the support number, you may first hear a recorded message lasting approximately 30 seconds (for example, suggesting that you visit an online support page). You can simply wait for the menu options to be presented. Typically, selecting "1" for business users and then "1" again for technical support will guide you to the appropriate support flow.
In some regions, the initial interaction may be handled entirely by an automated system. To help you prepare, below is an example of the questions you may receive and the recommended responses:
What kind of problem are you experiencing?
Answer: Authenticator
What product are you using?
Answer: Office 365 for Business
Is this a school or work account?
Answer: Work account (or Corporate)
Are you an administrator?
Answer: Yes
Are there any other administrators in your organization?
Answer: No. I am the only administrator in the tenant.
Do you need a Service Request?
Answer: Yes. I need to open a support ticket. Please transfer me to the Data Protection team.
I hope this information helps you successfully escalate your request and regain access to your tenant. If you have any updates or additional questions, please feel free to reply to this thread. I will be happy to continue assisting you.
Warm thanks.