Can't activate Microsoft 365 Developer Sandbox – phone number already in use

Question

Hello,

I joined the Microsoft 365 Developer Program with my personal account (email available upon request) to prepare for the PL-300 certification. However, I didn’t receive access to the sandbox environment.

When I try to create a new one, I get an error saying that my phone number is already associated with another account. The original sandbox may have expired, but I cannot proceed now.

Also, the support link inside the Developer Dashboard returns a 404 error, so I can’t submit a support request through the usual channels.

Could someone from the Microsoft team please help me unlock my phone number or activate a sandbox for my current account?

Thank you very much