Hi, I'm John! I will help you with this.
Are there any other admins in your organization who could reset your multi-factor authentication settings for you?
If you are the only Global Admin and don’t have any alternative verification methods set up (like backup phone or email), then the only way forward is to contact Microsoft 365 Business support directly via phone https://support.microsoft.com/topic/customer-service-phone-numbers-c0389ade-5640-e588-8b0e-28de8afeb3f2 They’ll ask you to verify your domain ownership and can help reset the MFA requirement so you can get back into your account.
Or, you can create a temporary trial Microsoft 365 Business account and use it to reach Microsoft Support directly through the admin center, that often helps you connect with the right support team faster:
- Create a trial account here: https://www.microsoft.com/microsoft-365/business/microsoft-365-business-standard-one-month-trial
- Using the trial account, Sign in to Microsoft 365 admin center https://admin.microsoft.com
- Select Support > Help and support, enter your question and select Contact support.
I really hope this information is helpful! Let me know if you have any further questions or concerns.
Regards,
John J.D.