Let me explain you in more detail here.
I have created a user under the main account faisal@7v840c.onmicrosoft.com in the portal admin.microsoft.com
The user created with the domain used for SBC is abcsbc.com and the new user is faisal.ahmad@abcsbc.com
This domain abcsbc.com was verified from the main account faisal@7v840c.onmicrosoft.com and I have added all the routes to my AWS domain registrar from Microsoft.
So what do you think now?