Withheld payment in harbour (6)
I believe the answer is:
docked
'withheld' is the definition.
(docking is a kind of withholding)
'payment in harbour' is the wordplay.
I cannot quite see how this works, but
'harbour' could be 'dock' (I've seen this before) and 'dock' is located in the answer.
The remaining letters 'ed' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for docked that I've seen before include "Cut short" , "Berthed" .)