Myntra.com — Refused exchange

I ordered a sweatshirt from Myntra and it was delivered today. As soon as I opened, I found stains near its neck. Therefore I tried to request for exchange. However, Myntra says they do not provide exchange services at my address.. In fact, any of my addresses. I do not understand! If it is possible for them to deliver, why not exchange? Also, this was never mentioned when the actual order was placed. I tried 'contact us' on Myntra where the bot gave me a number. I attempted a number of times but the call never got connected. I would like to receive a fresh piece without any defects.