I am unable to change my scoutbook username

I am logged into scoutbook with my school email, but my school has now changed their policy to make my school email unable to operate under third party services. I have now changed my scoutbook email to a gmail, but my scoutbook username is still my old school email. I have tried to change my username, but I am unable to. How can I change it?
My BSA number is 135286838.

thank you

following as Troop 813 Dubai Advancements team

The only way to do this is to talk to council and for them to send in a National Membercare ticket