Outstanding debt (7)
I believe the answer is:
arrears
'outstanding debt' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for arrears that I've seen before include "If in these, the money is overdue" , "In these, one is behind with payments" , "Amount needed to be paid back" , "In these, payment is overdue" , "Outstanding payments" .)