
Here are my suggestions
- If you changed your device recently, do you have your old device? Can you authenticate by the old device?
- Do you have the option to authenticate via other means like email?
- Did you purchase from a reseller? Can the reseller use delegated admin to help you reset your account?
- If you are the only administrator, and there are no other means for you to get access, then you have to contact the Microsoft Global Support phone numbers
- These phone numbers have Interactive Voice Response agent (IVR). Due to phone connection quality, and also your accent, some people have feedback that they have difficulty talking to a person. So using a good phone line, speaking slowly and clearly, might be an important factor.
- Others have feedback that following this script might be helpful
IVR: What kind of problem are you concerned about?
You: Authenticator.
IVR: What kind of product do you use?
You: Office 365 for business.
IVR confirmation: education or company account?
You: For companies or For education
IVR: Are you an administrator?
You: Yes.
IVR: Do you have the other administrator in your organization?
You: No.
IVR: Do you need a... Service request?
You: Yes
Hope this helps