October 2015
I met Xalek on Ilum and accidentally told him that I wanted him as an Ally, instead of a blind follower. I thought I was just being nice, but it turns out I turned him down. HE IS THE MAJOR REASON WHY I PLAY INQUISITOR, AND NOW HE'S GONE. There needs to be more of an indication that you're turning them down, before you pick the "wrong" answer. And is there any way for me to get him back? He's just too good of a character, and I can't believe I can't get him now.
October 2015
You may want to try resetting your quest progress, if you haven't already finished the quest. And if that's possible, I'm not sure if it is. Otherwise, no. If you haven't already used your free 60 you could use it to create a new inquisitor.