Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Personal accounts are kept separate from business ones. Your personal account can be accessed via https://account.microsoft.com/services .
Phone support is very limited for individual accounts; that is correct. There is chat support via https://support.microsoft.com/contactus .
You manage your business account via https://admin.microsoft.com . That is where you manage payments, assign licenses to user accounts (e-mails), etc. See also https://learn.microsoft.com/en-us/microsoft-365/admin/?view=o365-worldwide . (Maybe the primary issue here isn't with your business subscription.)