Disappointment with TV returned (7)
I believe the answer is:
setback
'disappointment' is the definition.
(thesaurus)
'with tv returned' is the wordplay.
'with' means one lot of letters go next to another.
'tv' becomes 'set' (I've seen this in other clues).
'returned' becomes 'back' (I've seen this before).
'set' put next to 'back' is 'SETBACK'.
(Other definitions for setback that I've seen before include "Snag" , "Hitch" , "Check" , "unfortunate event" , "Reversal of fortune" .)