Treated cruelly in short conversation -- upset about it (10)
I believe the answer is:
brutalised
'treated cruelly' is the definition.
(treated brutally)
'short conversation upset about it' is the wordplay.
'short conversation' becomes 'tal' (I can't justify this - if you can you should give a lot more credence to this answer).
'upset' becomes 'bruised' (bruised can mean upset or badly affected).
'about it' indicates putting letters inside.
'tal' going into 'bruised' is 'BRUTALISED'.
'in' acts as a link.
Can you help me to learn more?
(Another definition for brutalised that I've seen is " treated very badly".)