So Final Fantasy Versus XIII was never made?
Yes and no...
FF13VS was supposed to be the PS3 exclusive game after the whole FF13 not being exclusive on PS3 debacle. Square Enix said they were working on the game, which it was easy to see that they weren't due to the fact that FF13, FF13:Part2, FF13:Part 3, FF14 and FF14:A Realm Reborn all announced/made before FF13VS was even shown again at E3 2013.
At E3 2013, they showed gameplay (more like directed gameplay) of FF13VS but at the end of the trailer the name was changed to FF15. (Probably changed so they could release it on PS4, XboxOne and maybe PC)
Gotcha, thanks for the explanation.