420 IPC case filed against father in cheque forgery matter

Sir, this incident happened with my father. He is a manager in a reputed bank. During his tenure as a branch head, a cheque of rs. 4 lacs was presented at cash counter for payment. The presenter was his wife and the cheque was not forged. My father received a call from an unknown number on the same day before the cheque got cleared that the presented cheque should not be encashed and the caller introduced himself as the owner of the cheque. But since the mobile no. was not present in his account, he was unable to verify the identity and told him to stop the payment in writing that same day. My father cleared the payment to his wife on absence of any application for stopping payment to that cheque. Now the person has filed a FIR against my father under section 420 and is blaming him for all the incident happened. Please guide what should be done in this case