Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Dear igor Tsoy1,
Thanks a lot for your patience and understanding!
About how to delete domain from the old account, please kindly try to refer to these two documents: Perform an internal admin takeover and Remove a domain
In addition, sorry as I said last time, since you are the only administrator within your organization, we do not have permission to help you, in order to save your time, I still recommend that you directly by contacting our phone team dedicated to administrator-related issues for more support, please refer to: Get support for Microsoft 365 for businessand Global Customer Service phone numbers
Wish you have a wonderful day and always stay safe!
Best regards,
Kerry