KB is right you can call it what you want, but longtime wrestling fans will always call it TNA. It's the name that most of us grew up watching it under.
I'll give you an example. The Rogers Centre here in Toronto used to be called Skydome, I still call it that to this day even though they changed the name years ago. A lot of people who live here still call it that. So yea as much as Jarrett and Anthem might want it called something else, as long as you have the same roster, same set and same fans every week, the TNA name will live on.
EDIT: Just look at the name of this forum to see what I mean.