Previously Microsoft dealt with Microsoft provided PSTN number porting and number provision issues via some specific email addresses (like ptneu@microsoft and gcstnmsd@microsoft). As of July 22, 2021, the email system has been retired and replaced with a new dedicated portal. The portal is at https://pstnsd.powerappsportals.com/ but can also be reached via the Teams Admin center:…
— Read on tomtalks.blog/2021/07/new-microsoft-teams-phone-number-service-portal-in-teams-admin-center/