Organisation providing a service (6)
I believe the answer is:
agency
'organisation providing a service' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for agency that I've seen before include "Cagney (anag.)" , "Through which something is accomplished" , "Recruiters possibly" , "Travel ..., advertising..., employment" , "Business that conducts business on behalf of others" .)