Sole admin locked out due to lost MFA (no backup method) - tenant 3netcomunicacionescomco.onmicrosoft.com

Hello. I'm the IT lead for a small business and lost access to Microsoft Authenticator after replacing my phone. I have the correct password for the affected accounts, but the only registered MFA method is Microsoft Authenticator (no backup phone or email as a sign-in verification method), so I cannot complete sign-in or reach the admin center to fix it myself.

Affected accounts: ******@3netcomunicacionescomco.onmicrosoft.com and ******@3netcomunicacionescomco.onmicrosoft.com

Tenant domain: 3netcomunicacionescomco.onmicrosoft.com (custom domain 3netcomunicaciones.com.co). I'm not aware of another account with the Global Administrator role available. The subscription is billed directly to a credit card (direct purchase, no partner/CSP involved). I can verify tenant ownership: I have access to the alternate recovery email configured on one of the accounts and to the billing details.

Could you please advise on the process to verify identity/tenant ownership and reset the MFA method for these administrative accounts? I'd prefer to share further sensitive details (tenant ID, billing info) through a private channel once support requests them, rather than posting them here.

Thank you in advance.