Remove OD4B specific Site collection Admin

Hi 

I need to remove a specific user (ben@contoso.com) from all the users OD4B (somehow he managed to make him a Site Collection Owner on all users - along with the user)

So I need some help to a powershell script that runs on all the users OD4B

I've tried this one blow - but that doesn't do the job - it just 'examine' - doesn't remove the SCA user I've defined

https://www.jijitechnologies.com/blogs/add-remove-secondary-site-collection-admin-to-all-onedrive-for-business-users