Punjab National Bank [PNB] — refund not processed from amazon.in

I have returned a tshirt ordered from amazon.in and they have generated my refund on 3/3/2020 with refund reference number[protected] but the amount of ₹419 hasn’t been credited to my bank account even after 10 business days. Pnb’s customer care is saying they cannot check the status of refund reference number and can only check account balance. Amazon’s customer care is suggesting to charge a dispute form against pnb as they have done their part and for confirmation they have provided the reference number for refund of ₹419.00.
Please process my refund through this reference number[protected]