Sole Global Administrator locked out by MFA – need Tenant Recovery escalation

I am the sole Global Administrator of a Microsoft 365 Business tenant and am completely locked out of the Microsoft 365 Admin Center due to MFA. I replaced my mobile phone and no longer have access to the Microsoft Authenticator registration associated with my administrator account. I know my password and can reach the MFA challenge, but I cannot complete authentication. There is no other Global Administrator or Privileged Authentication Administrator in the tenant who can reset my authentication methods. I have already opened a Microsoft Support case. Microsoft contacted me requesting additional information, which I supplied. I have subsequently followed up several times but have received no further response. I have also contacted Microsoft 365 Business Support by telephone. After approximately an hour with a support representative, the call was disconnected without resolution or a callback. I have created a separate temporary Microsoft 365 tenant so that I can access the Admin Center and communicate with Microsoft Support, but I still cannot get the original tenant recovered. My understanding is that when the sole Global Administrator is locked out and no other privileged administrator exists, Microsoft Support needs to escalate the matter to the appropriate Data Protection / Tenant Recovery team for ownership verification and recovery of administrator access. Can a Microsoft moderator please advise how I can have my existing support case escalated to the appropriate Tenant Recovery/Data Protection team? I can provide my existing support case number and all necessary verification information privately through an authenticated Microsoft channel. For security reasons, I will not publish my name, email address, telephone number, domain, tenant ID, billing information or support case number in this public forum. This is an active Microsoft 365 Business tenant and I need assistance getting the existing support case to the team authorised to perform the recovery.