You can remove users (disable their access to the subscription) through the Admin Portal.
There are two ways to get to the user management tab from the Admin Portal:
On the Manage teams page, click on the number of team members. After doing this, you will be immediately redirected to the page with the members of the team you clicked on.
On the top bar of the admin page, click Manage users. The page displays all users until you specify search filters.
Find the required user on the page with all (or filtered) members of the organization.
On the right, click Remove.
Repeat these steps with as many users as you need.