Total amount returned (3)
I believe the answer is:
'total' is the definition.
(I've seen this in another clue)
'amount returned' is the wordplay.
'amount' becomes 'N' (N is an example).
'returned' becomes 'et' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
Can you help me to learn more?
(Other definitions for net that I've seen before include "After expenses" , "Meshwork" , "Score a goal" , "Ultimate" , "Make" .)