Amazon India — Amazon denied refund after return of the product

ORDER #[protected] was retuned and Pickup Tracking ID:[protected]. It was picked up by the Amazon agent which was updated in their system. Then there was no update. After a month I contacted customer care. They said I have sent the wrong item and accused me of counterfeit return and denied refund. On asking what is the item they have received they have confirmed that they don't know. At this point of time I do not have the product nor the refund from Amazon.