Paytm — Received wrong product but they are not replying

Address: Pune, Maharashtra, 411008

Website: paytm.com

I bought boxer shorts from paytm but they sent me different sizes one large and other small. Now it I of no use to me. I raised the issue but they are not replying to any of my tickets. I raised this issue to the paytm grivarence form but still no reply from them. All they are saying that it cannot be returned as per sellers policy. It means seller can send a bag of sand to me and I cannot return it because its sellers policy.