I assume you are talking about http://www.funtrivia.com/team_info.cfm?gid=26937
which matches the criteria you are describing.
This is a group you created yourself, 10 days before the one you are leading now (Jul 27, 2011 vs. Aug 6, 2011). It seems you handed over leadership so that you could leave and form a new one. Now a newly joined player has taken it over and reactivated it.
Of course with them being older, that would actually mean they have the older rights to the name and identity. So unfortunately we cannot help you - there is no foul play involved, just a player taking possession of something you discarded and left around free for the taking.