Hi Alan
Thank you for your query and your patience. Microsoft Education made it easy for school end-users to sign up for Office 365 Education without an IT Administrator, for faculty to quickly leverage on our free software.
The way to get administration control is as follows https://docs.microsoft.com/en-us/microsoft-365/education/deploy/becoming-an-admin-in-office-365-education
The documentation describes why this is happening to you, and a step-by-step guide on how to take control as an IT Administrator. Perhaps you can assign between two to five IT Administrators to manage the Office 365 tenant for your school.
Echoing VincentChoy, do contact a Microsoft Partner in your country if you're looking for deployment and administration advise. These partners can then transact licenses to you when you decide to upgrade software in future.
For educator continuous professional development, Microsoft has a free resource here, where we tweak courses of software to suit teaching & learning. The repository has a focus on pedagogy as well. https://www.education.microsoft.com/en-us
Kind regards,
Li Kuan