The same thing happened to me, but I was told that the Genealogist badge is full membership!
If someone invites a family member they don't need to volunteer and be confirmed. You've already confirmed them, so they don't have to volunteer.
I have not had any problems contributing to WikiTree without the Volunteer Badge although I would have liked to have one. I just let it go.
But if you still want the volunteer badge you could e-mail firstname.lastname@example.org.