Paytm - Replacement refused

I have purchased a seagate * tb hard disk on **th of july and recieved on **th of july.It was a defected product so as per return policy which is clearly mentioned in the product description item should be replaced by seller but my replacement was refused.Although it is covered under warranty and they are suggesting me to visit service center.But my question to these paytm guy is that why u have put a return policy on your own?By going through this return policy I have decieded to purchase my hard drive from paytm.You can go through the return policy in the screenshot.It clearly means they are misleading their customers on the return policy.
Now they are saying that return policy has changed.
please go through the screenshot.