Punjab National Bank [PNB] — Refund not received

On October 5 des, 2020, I my refund has been initiated in my account massage come from amazon.but refund is not credit in my account .so I asked Amazon, they said it has been sent to my account and provided me with the refund reference number and asked me to call the bank's customer care. I called PNB cc 4 times but everytime the person said they don't know what these things are and they can't help me with this and asked me to contact the branch. but they aren't taking any action. Please let me know about the proper solution for this problem asap.

Amazon refund reference number:[protected]