Cannot receive text/email verification code

Good day Jethro and I’m sorry to hear about the difficulties you and your friend are experiencing.  

Just to gently clarify before going any further, this forum is separate from Microsoft Support. Forum users, moderators and Microsoft external staff cannot access user accounts or directly escalate cases. For security and privacy reasons, account-specific issues can only be handled by Microsoft's dedicated support teams. 

Error 399287 indicates that Microsoft could not complete the identity verification request, possibly because the verification method is unavailable or temporarily blocked.

Since there are no other admins available to reset MFA, identity verification and account recovery can only be handled by the Microsoft Data Protection team, which is authorized to help restore access to the admin account. Please try calling the applicable support hotline for your region again: Customer service phone numbers - Microsoft Support  

Note: I understand that you have tried contacting Microsoft Support without success. However, please try the example scripts below to help ensure your request is directed to the appropriate team. 

When contacting Microsoft, be prepared to verify your friend's subscription ownership by providing details such as the organization name, billing or payment information, registered phone number and alternate email address. 

Once your friend's identity is verified, the privacy team will be able to reset the MFA settings. Your friend can then reset the account in the Microsoft Authenticator app using the current device or choose a different authentication method to sign in. Tips for navigating the IVR:  

(When you call the support number, you may hear an introduction of about 30 seconds such as "you can visit the link...". You can ignore this introduction and wait until you are presented with the options. Then press "1" as a business email user, and again "1" for technical help.)    

In some countries, an automated voice system is used. Example of a dialogue: 

IVR: What problem is bothering you? 

Client: Lost access to the only admin account. 

IVR: What product do you use? 

Customer: Office 365 for business. 

IVR: School or Business account? 

Client: Business account 

IVR: Are you an administrator? 

Client: Yes. 

IVR: Is there another administrator in your organization? 

Client: No. I am the only admin in my tenant.     

IVR: Do you need to create a support ticket? 

Client: Yes. I need to create a ticket. Please send me direct to the Data Protection team. 

In case you are unable to contact the frontline support: 

Consider signing up for a trial subscription to create a new tenant. Visit Microsoft 365 Business Plans and Pricing | Microsoft 365. 

Once the new tenant is set up, you can access its admin center and submit a support ticket through Microsoft 365 admin center > Support > Help & Support to contact the Data Protection team regarding the previous tenant. Please remember to cancel the trial subscription after the issue is resolved, as this will help you avoid any accidental billing. You may prefer the following resource for detailed instructions: Cancel your Microsoft business subscription in the Microsoft 365 admin center | Microsoft Learn 

If the organization's subscription was purchased through a partner or reseller, contact the reseller's support provider to help open a service request on your friend's behalf. 

I hope this helps point you in the right direction. If you have any questions or need further support, please don’t hesitate to reach out at any time. 

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