At the end of the quest, can the [Attack] option update the quest similarly to the other options so that it can be turned in? The fight seems (understandably) impossible, but the quest can't be turned in if you decide to flee.
Also, I'm not sure if this is done purposefully or if it's a bug, but the "boss" doesn't ever stop summoning. I saw as many as 8 before I decided it was time to leave.
EDIT: quest name is Prophesied, woops.
Considering there's two other ways of finishing this quest other than attacking, I think having to abandon it because you were rudely unconvinced about the prophet's words a fair thing.
You bit over more than you could chew. You did not handle the problem, you fled from it.