Please, don't yell. Please.

Did you go into the dungeon in hard or normal mode? Only normal mode will count in this quest. Rather than talk to the NPC, open your journal and see what the objective is, then complete it. If you did normal mode and are still having problems, then, again, in the journal, try to abandon it. If none of this works, then you should start a live chat or call SE directly. If they cannot help you right then, then they can create a support ticket for you to esculate the issue to whomever can help you.