Bank Of India — refund amount from amazon not came in my bank account

Website:

Amazon.in

I ordered a product (BoAt stone portable Bluetooth speaker) on Amazon but for few reasons I request for replacement.This order replaced by 19 Aug 2018. But new speakers are also damaged so I request to return. Return was completed on 26 Nov 2018 and also they i got message from Amazon is "your amount is refunded". But I didn't get message from my bank. I checked my bank passbook but no transaction showed with that reference. So I call to Amazon they said, "fill online dispute form ". But bank manager said "online dispute form is fill only when your transaction done online from bank and then this money when refunded then on this case online dispute form is filled" Refund reference no. for transaction is :[protected]
From Amazon mail, my refund transaction has done on 26/08/2018, but when checked my passbook then no any transaction found with that reference.
Refund for order[protected]order id) of 999.00 RS.