Amazon.in - Product Returned but denied Refund

Product name: Bajaj GX* Mixer Grinder, ***W, * Jars (White)
Order date: ** Feb ****
I have returned the product on *st March in the afternoon. I got the message from delivery boy in the night stating that your order was cancelled mistakenly, place a new order. I talked to amazon customer care on the same day, she said everything is fine, you will get the refund in ** days. I didn't get the refund in ** days, again I talked to amazon care, he assured me that you will get the refund in * days, but issue didn't get resolved. Again I talked to these guys, they gave me time for * days, then again for ** hrs then again for * day. and finally they have refused to initiate the refund.
Although I have returned the product, and delivery boy is confirming the same. he is saying that product is their office. Still these guys aren't ready to resolve the issue.
I am attaching chat screenshot in which they had assured me for the refund. also the screenshot of the message that I got from the delivery boy.