I cannot unblock my sons account

My sons xbox account is linked to Email I cannot access, (*** Email address is removed for privacy ***) I cannot unlock, I can reset password but each time i doit tells me someone else was using account. the Email address that your system wants me to useis no longer vailad, and have tryed to contact the xbox avocday team but were not able to help Ref sr1208478084, This matter has now been on going for 9 months, Inwas on phone today to xbox support and talked with a fella david he took me step by step to resovle but advised me to contact hotmail support team. Id like you to understand my son has issuses and has trouble with reading and im really let down with xbox many calls emails time and money ive spent trying and chasen this matter. Ive 3 sons all have xboxs and i spend fortune on games mircosoft ponits they all have gold memberships im so Angry how valued of xbox costumer youve made me feel, my sons accout to be put on hold took away click button and no one to help when trying to get it downloaded backmon to his xbox how much stress brought to my home over my son haven no sky tv on his xbox due toxbox deleted it, i would like this matter passed to someone who can Help !! Martha logue