Confederate company set back schedule to steal from everyone (12)
I believe the answer is:
collaborator
'confederate' is the definition.
('collaborator' can be a synonym of 'confederate')
'company set back schedule to steal from everyone' is the wordplay.
'company' becomes 'co' (abbreviation).
'set back' says the letters should be written backwards.
'schedule' becomes 'rota' (I've seen this before**).
'to steal from' becomes 'rob' (I've seen this before).
'everyone' becomes 'all' (I've seen this before).
'rota'+'rob'+'all'='rotaroball'
'rotaroball' back-to-front is 'llaborator'.
'co'+'llaborator'='COLLABORATOR'
(Other definitions for collaborator that I've seen before include "One working jointly" , "Partner" , "Quisling" , "who takes part in jobshare?" , "Fellow worker" .)