Pepperfry Style Homez - Small size delivered of bean bag

I had ordered XXXL size bean bag from pepperfry which got delivered to me on *st Oct, ****. However as soon as it was delivered I noticed that even though on that product the size is mentioned as XXXL, but actually it's size is very small may be L or XL. As I have used XXXL bean bags earlier I can feel the size as very small as compared to standard XXXL size and I can not sit over it comfortably. And I raised return request on the same day. However I got reply from them saying return is not possible as the item delivered is same as mentioned in their app. I had even sent *-* mails to their grievance officer but did not get any reply. So I want to file complain against them to refund this product.