Flipkart - Received Defective Product

I purchased this laptop from flipkart.com on ** october **** it delived to me on ** october ****, when i opened the box and checked keyboard was defective, then i called to asus customer care, customer support registered my complaint and asus service engineer visited to my location and diagnosis my device and found keyboard issue, he suggested me to to return on Flipkart.com as soon as posible i called to flipkart support he said that same device is not in stock, i tried many time but same reply i got, after * or * days i mailed to flipkart team, custome support told me to wait for * days for revert, i wait and got the reply that was not proper and understandable, now flipkart is saying this cannot be returned as returned period is over, I have also got the DOA letter from brand authorised service center for replacement for the device.