Flipkart not refunding money for returned product

I have order a Reebok shoe from flipkart on 25th July And I received this product 26 July. And same day I request a return for large size shoe,
On 27 July flipkart courier partner taken my product for return And send me confirmation return done sms. Then I called flipkart customer care for my product refund money and he told me my refund is not possible because I complain for missing product and my return request reject. I mailed to flipkart with screenshot of successfully return sms but they all told me my return request failed my refund not possible. I goes to my local flipkart courier partner and he told me they already send this product for return
Now I ask to flipkart where is my product but flipkart not reply
How can I do sir
When flipkart return received this product so why my refund not possible
I never complain for missing product I only complain for large size product
Is I complain for missing product so why courier partner taken my product return. Now my product missing and money deduct how can I do.

Victor Mukherjee
Midnapore 721101, West Bengal
Email: vxxxxxxxxx1@gmail.com