re-activate a user in free edition

I deactivated a user, as they are leaving the company and wanted to replace them with a new user.

However it won't allow me to add another user in free addition.

I then tried to re-activate the original user to change the name but it won't allow me to do that either.

Can anyone assist me with this? I'm confused as to why originally I was allowed to have 2 support reps but now I'm only allowed 1.