Punjab National Bank [PNB] — not filing of charge dispute

Dear sir, in my account rs 8980 is refund money of my purchasing is credited by amazon india at 11/07/2018 . Which should be reflect in my account 16/07/2018 . Many times i called customer services of punjab national with refund reference no[protected] but they denied to take complain and process of charge dispute file. Kindly provide me proper solution and guide bank to locate my refunded transaction.
Yours Komal Saini s/o Rampal Saini