Unable to sign in to my account, no access to email for 2FA and old number on account

Hi,

I pay £28.99 a month for my Xbox on a 2 year plan and it comes with Ultimate Pass.

I'm unable to sign in because I my son kept putting the password in wrong and he has locked all of my accounts.

I can't sign in because I didn't have authenticator set up and I no longer have the phone number registered. Microsoft will not help and keep asking me to fill in the recover account form which is impossible to do and they will not recover my account.

I cant afford to sign up to ultimate pass again on a new account and it is already included in the £28.99 that I already pay.

How can this be sorted?

Thanks

Jason

:)