Pepperfry.com - Pepperfry delivered a sagging mattress and denied replacement or return and refund

We ordered a mattress on October **th, **** and it was delivered on **th October, ****.
The mattress was delivered to us rolled up, with sagging more than * inches and with a yellow stain. Their website says it will be delivered Flat, and also the firmness is rated * but it is a * or *. Clearly the product has misleading images as the product was faulty. We had ordered a similar mattress in May and had no such issues with it.
Pepperfry denied us a replacement or a return and refund but we feel cheated and betrayed. We contacted the customer care, the escalations team and the grievance team but everything is handled by the escalations team and they denied everything. This is causing us a lot of problem as we cannot use the mattress and it is taking up space by just keeping it in a corner. We have also spent ***** and it feels wasted.