Telephone fault may mean a reporter missing it (8)
I believe the answer is:
deadline
'it' is the definition.
The definition suggests a singular noun which matches the answer.
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for deadline that I've seen before include "that shouldn't be missed?" , "Latest time for completion" , "Target time" , "Point in time when something must be completed" , "Cut-off point" .)