If you completed Secondary Quest: King's Gambit first, then this quest becomes unavailable as it's a set up of another quest (The Cave of Dreams) where Madman Lugos asks you to help his son, Blueboy, who's dead after King's Gambit so this quest becomes pointless!
This quest will be available after ( The Phantom of Eldberg ) Quest.
And you must complete (The Cave of Dreams) first before starting this one.
if you want to get ( AN UNPAID DEBT ) quest then do the following during this quest :
When you get in the prison talk to the guard and ask him the last question and don't try to get out by Axiiing him, then go talk to Simun and let him help you get out of the prison, then complete any other quest, so (AN UNPAID DEBT ) ques will be unlocked
the sequence of quests will be like this:
- The Cave of Dreams
- The Phantom of Eldberg
- Stranger in a Strange Land
- any other quest
- AN UNPAID DEBT