I need to remove my Phonenumber from an old Outlook-address

I need to remove my Phonenumber from an old Outlook-address so I can create a new DeveloperTest-Account.

I can't remember the password and questions to reset it. It is not used for the last 8 years or so.
I need to get the Developer-test so I can create a Tenant with E5 for testing before SC-300