Flipkart — They are not returning my money for return product

I made a purchase of safari suitcase on aug 11 but when I received the item their was size fit issue so I decided to return the item. I made a return request on 16 aug which was under 10 days return policy. But after thata nobody comes to pickup my return and I have raised more than 6 complaints, made 20 calls and talked to different customer support executives and their seniors regarding the issue but none of them has resolved the issue and now they are ignoring my calls and account.
I wish to take strict action against their customer support policy