So-called "free users" should have ALL their rights checkboxes unchecked, 100%, including the right for the Free Use section.
A paid user (full user, normal user) is someone who has access to the system, a user who has credentials to view, create, or update something. It's someone who can log in, in normal mode or internet-kiosk mode.
A free user (team member) is essentially not a user of the system, but just a named person in the system, for whom you can keep records of. A free user does not have access. This is beneficial for example when someone leaves your company, then you can convert the paid user to a free user instead of deleting him/her, to keep records of that person's actions.
Please do not worry, the billing system does not take money automatically for additional services like:
Upgrading pricing plans.
Purchasing Skype training hours.
You can ask us to delete this incorrect invoice by opening a support ticket, or you can wait till 14 days has passed, after which it will expire automatically.
In any case, such proforma-invoice doesn't impose any obligations on you.
This is the correct behavior. Regular users cannot change their passwords if they have forgotten them.
The manager of the person in your company, the account administrator, must change the password in Settings -> Human Resources -> particular user's data.