Lost admin access account credentials

Question

Dear reader,

I have lost access to the admin credentials for my Microsoft work account (the address is not mentioned here because of security reasons). I use this address for freelancing, so I am the only admin (and user) of the address. Is there any way to reset the password of the admin account? I am able to prove my identity with the Microsoft Auth app (for Azure services).

I followed these steps:

After having filled out the address and the captcha:

After which I press "Contact support". Whathever option I enter next has me end up at this page:

What should I do? Thanks a lot in advance.