Prison for a debt collector who has gone wrong (7)
I believe the answer is:
dungeon
'prison for a debt collector who has gone wrong' is the definition.
'dungeon' can be an answer for 'prison' (thesaurus). I'm not sure about the rest of the definition.
'collector who has gone wrong' is the wordplay.
'collector who' becomes 'dun' (I can't explain this - if you can you should believe this answer much more).
'has' indicates putting letters inside.
'wrong' indicates anagramming the letters.
'gone' is an anagram of 'ngeo'.
'dun' going around 'ngeo' is 'DUNGEON'.
Can you help me to learn more?
(Other definitions for dungeon that I've seen before include "prison the result" , "Unpleasant cell" , "Keep" , "Uncongenial accommodation" , "Place of confinement underground" .)