Account number used or charged (7)
I believe the answer is:
accused
'charged' is the definition.
(I've seen this before)
'account number used' is the wordplay.
'account' becomes 'ac'.
'number' becomes 'c' (C is an example**).
'ac'+'c'+'used'='ACCUSED'
'or' acts as a link.
(Other definitions for accused that I've seen before include "One tried" , "Defendant appearing on a criminal charge" , "Person being charged" , "Indicted" , "Blamed" .)