Pepperfry - Misleading listing of product and refusal to give refund

They are listing ergonomic office chairs on their website which were on sale. One of them had a headrest and I wanted to use it as I have back problems. However, when the chair arrived, I found out that the chair doesn't actually have any support and will lean back entirely to almost *** degree position at the minimum weight applied on to it as one would when sitting on a supposed "ergonomic" chair meant for back support. I filed the product as defective as it doesn't serve it's intended purpose at all, and there is no mention whatsoever in the website that there is no locking mechanism for the back of the chair. However, pepperfry is refusing to address the issue and is saying that they don't accept refunds.