Pitch working, used (3-4)

I believe the answer is:

put-upon

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'used' is the definition.
(synonyms)

'pitch working' is the wordplay.
'pitch' becomes 'putup' (I can't justify this - if you can you should believe this answer much more).
'working' becomes 'on' (e.g. a machine is working or on).
'putup'+'on'='PUT-UPON'

Can you help me to learn more?

(Another definition for put-upon that I've seen is " Taken advantage of".)

I've seen this clue in The Times.

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