Take advantage of customers about (5,2)
I believe the answer is:
trade on
'take advantage of' is the definition.
(thesaurus)
'customers about' is the wordplay.
'customers' becomes 'trade' (I've seen this before).
'about' becomes 'on'.
'trade'+'on'='TRADE ON'
(Other definitions for trade on that I've seen before include "Make use of for one's own advantage - it's not dear" , "Take advantage of" .)