Company pressure stops workers backing charity collections (9)
I believe the answer is:
compendia
'charity collections' is the definition.
'compendia' can be an answer for 'collections' (a compendium is a collection of information). I'm not sure about the 'charity' bit.
'company pressure stops workers backing' is the wordplay.
'company' becomes 'co' (abbreviation).
'pressure' becomes 'p' (abbreviation).
'stops' indicates putting letters inside.
'workers' becomes 'men' (men can mean staff or employees).
'backing' becomes 'dia' (I can't explain this - if you can you should believe this answer much more).
'p' put into 'men' is 'mpen'.
'co'+'mpen'+'dia'='COMPENDIA'
(Other definitions for compendia that I've seen before include "summaries of work" , "Lots of puzzles" , "set of encyclopaedias" , "Dome panic (anag) - summaries or collections" , "books" .)