Provider of charge account, cocaine addict (7)
I believe the answer is:
accuser
'provider of charge' is the definition.
'account cocaine addict' is the wordplay.
'account' becomes 'ac'.
'cocaine' becomes 'c' ('C' can be a synonym of 'cocaine').
'addict' becomes 'user' (I've seen this before).
'ac'+'c'+'user'='ACCUSER'
(Other definitions for accuser that I've seen before include "One who brings a charge" , "One who brings charges" , "origin of charge?" , "One bringing a charge" , "One charging" .)