Microsoft account blocked

My son is unable to use Xbox live as his Microsoft account has been blocked under Code 8015D02E. The recovery email on the account no longer exists, so we tried the account recovery form. However, despite 3 attempts we could not provide enough info to verify ownership. He has no credit card, does not use his @live.co.uk email to send or get emails . Have tried @microsofthelps and @xboxsupport on twitter for assistance and they referred me here. Have submitted a Microsoft service request which ended up back at the account verification form again. I seem to be stuck in a loop. Can a password reset link not be sent to my alternate gmail or if I provide a number by SMS to me?