Sorry, nothing works! (4)
I believe the answer is:
oops
'sorry' is the definition.
(I've seen this before)
'nothing works' is the wordplay.
'nothing' becomes 'o' (looks like zero - 0).
'works' becomes 'ops' (I've seen this in other clues).
'o'+'ops'='OOPS'
(Other definitions for oops that I've seen before include "Exclamation after mistake or minor accident" , "Something's been spilt!" , "I've made a mistake!" , "I've messed up" , "Exclamation on making minor error" .)