I bought it a long time ago and it's been sitting in my inventory as a gift ever since. I guess they're now selling the "definitive edition" instead of the goty edition.

You can find only the "Definitive Edition" of Dead Island and Dead Island: Riptide, the original games were removed, when the remasters were released. You can still activate and play the "old" games, just unable to buy them.
EDIT: I was too slow >.< :D