Aide receiving a service and fabulous treatment (7)
I believe the answer is:
panacea
'fabulous treatment' is the definition.
(mythical cure for all diseases)
'aide receiving a service' is the wordplay.
'aide' becomes 'pa' (abbreviation for personal assistant).
'receiving' indicates putting letters inside.
'a' becomes 'an'.
'service' becomes 'ace' (ace is a kind of service).
'an'+'ace'='anace'
'pa' enclosing 'anace' is 'PANACEA'.
'and' acts as a link.
(Other definitions for panacea that I've seen before include "Panpharmacon" , "A cure for everything" , "universal solution" , "Solution to all difficulties" , "that'll solve everything" .)