Amazon India — mobile refund for courier

We ordered a vivo v9 pro of 6gb from amazon and received a 4gb model instead. After a month of customer calls and complaints they contacted us telling that they don't have return pickup service for the delivery and hence we would have to courier it to the seller as a return parcel by ourselves and the amount spent for the courier will be reimbursed to us. However they didn't coordinate with the seller and he rejected our parcel which was returned back to us. On contacting amazon about the same they requested us to courier it again assuring that this time the will inform the seller in advance and reassured us that they will reimburse our courier charge and asked us to mail the courier receipts to them for their knowledge of how much we spent. We followed the instructions and couriered the mobile to the seller and sent the receipts to amazon's mail. However after a months mental harresment and all the inconvenience they refunded only the amount for the mobile order and haven't responded to refunding the courier charges which in total are 972+972= 1944
Since the order portal is closed after the refund of the payment for the mobile order there's no way we can contact them regarding this issue. There's no cooperation from amazon's side and despite their mistake of sending the wrong model they have harassed the customer. I want the refund of the couriers as promised to reflect in my amazon account asap and i want customer care to contact me on my registered mobile number registered to my amazon account [protected] email swarnim. [protected]@gmail.com