Punjab National Bank [PNB] — amazon refund amount not reflect in my account

Address:

Pali, Rajasthan, 306104

I purchased planet ayurveda tablets ₹680 from amazon and done full payment by debit card but order was cancelled and now amazon is saying that refund has been sent to your bank so contact customer service and file charge dispute. They had given to me reference number 727911 but customer service is saying that they can file nothing file charge dispute and can only check if money came to your account or not. Same behavior by branch also.
Now don't know what to do.
Acc no: [protected]
Acc holder: shubham deep singh