Myntra.com — Refusal to honor product return and refund

Myntra.com is refusing to take return and issue refund for an unused footwear due to their false claim that the product is used (as claimed by the pickup agent who didn't even know the difference between 'dust' and 'stain'). Even after thorough explanation that the product was unused and with the tags were intact, they are declining to take it back without even looking at the product again. Repeated explanation and prolonged interaction with the customer care executives has only resulted in so much of emotional trauma and waste of time. I have all proofs that the product is unused with absolutely no stain and I'm raising this complaint to take action against them for negligence and for falsely accusing the customers. Kindly curb their fraudulent practice.