Wrong credit to customer account by bank and customer refuse

I am a banker and one of the customers account was credited wrongly by huge amount of RS 24 lacs on informing him he gave a written letter that he will repay back the amount in two days and after one week also when he didn't repay back we went to police with the complaint police took action very late and on top of it refused to file FIR against him saying in legal procedure he had presented a cheque which was to be credited to his account but bank erroneously credited that cheque amount in his account instead of marking return that cheque of ICICI bank and saying us it as an civil case closed the file without taking any action please suggest was it right can't the banker do anything