Myntra - Refund declined

I placed a return request in Myntra for one of my orders Myntra picked up the product but declined the refund stating the product did not pass the quality check(It was used ). I Placed the return request within * hours of receiving the product, The product appeared Dull, uncomfortable and returned by someone before as there was another invoice except mine and they gave me already returned product hence I returned the product. Now, they have rejected refund and forcing me to accept the product. Why am I supposed to pay for this?