Imagine someone is indebted to you some amount of money. You are going to get it back. You friend who knows the issue, meets you and wants to ask about the matter. Which one of the following questions of the friend would sound natural here to you to be asked from the person in our question:
What happened with the money you were owed? Did you get it back?
What happened with the money they owed you? Did you get it back?
What happened with the money they were indebted to you? Did you get it back?
What happened with the money you were indebted? Did you get it back?
For me, the only choice which doesn't work here is the last one, but if there is a better way to say it (using the verbs "indebted" and "owe"), then please let me know about it.