EA child verification account - forgotten username

Hi

my son was asked to verify account on Xbox. When I click start verification it says can’t connect to ea servers. I tried for 2 hours and couldn’t access ea live chat. I am able to sign in to my ea account but there is no mention of a child there linked to it. The ea id it shows on that account is the same as what shows on his fifa game so how do I know what his child username is to be able to log in to his account to re send the verification email? I’m going in circles. If I put that username that’s shown on Xbox in to ea and forgotten password etc it just resets the account I’m using to log in 

please help!