Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hi,
Do you have access to your account? If so, may I ask what message or error when you try to billing add/change your email address?
Have you added the new email address first? Make sure that you have added and verified the email address first before changing your billing email address.
Is it a work/school email?
I look forward to your response.
Stay Safe!