Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Just so I'm sure I got this straight
- You have 2 factor authentication active on your account?
- You have a device that you didn't complete the setup on and thus unusable for 2FA?
- You do not have any devices setup as backup methods for your 2FA?
If all those are true then you'll never get your account back.
For those that find this topic in the future, ALWAYS setup multiple backup methods for 2FA. Do NOT rely on just a single device.