Xbox Live and the parent account

I recently removed a parent account (maybe 3 days ago) but I wanted to reconnect a new one now. Whenever I go to submit it after I put in all the correct information then it says that it can't be completed. I've also tried getting on the computer and trying
to see if I could change it in xbox live settings but it won't let me view it saying that there is an error message

:)

 

Unable to add son to xbox one

As above,

Select child
Sign in as parent
get to the 50c card authorisation, add card details
Then get card already exists on account - go through screens - again!!

Then after about 10 minutes updating account it fails with code 45468.7036976521340.5055251569016685

Go to xbox errorhelp - can't find it

Can anybody help please we are pulling our hair out on this

Just to say the card is on account from xbox and also Microsoft accounts linked to the parents account!

 

Can't access account because parent account is lost

My brother can no longer access Xbox Live. He is under age so he has a parent account attached to his Xbox Live gamertag. After microsoft changed the Xbox Live terms of service he needs this parent account to accept the new ToS so he can use Live. The
problem is, no one has used the parent account in a long time and we forgot the password. And we can't recover the password because the alternate e-mail for this parent account is an even older address that doesn't even exist anymore. And because the parent
account is so old we have no chance of being able to remember enough information to fill out the password recovery form. Ergo, my brother can't use Xbox Live.
We either need to find the password for the parent account or, preferably, change the parent account attached to his gamertag.