Left with bill for setter, obtained on demand (7)
I believe the answer is:
exacted
'setter obtained on demand' is the definition.
I can't tell whether this defines the answer.
'left with bill' is the wordplay.
'left' becomes 'exed' (I can't justify this - if you can you should believe this answer much more).
'with' indicates putting letters inside.
'bill' becomes 'act' (an Act of Parliament).
'exed' placed around 'act' is 'EXACTED'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for exacted that I've seen before include "Inflicted" , "Insisted on and obtained - in precise way?" , "'Claimed, demanded (7)'" , "Insisted on and obtained, say payment" , "forced out" .)