Paytm — Wrong Size Mattress

I ordered a Kurl-on Klassic Mattress from Paytm.com May 30, 2015 for Rs. 23, 303 of which 7000 was received back as cash back in paytm wallet. While ordering, i chose 'King Size' in the given dropdown on the product page. There was no mention of the dimensions on the product page on the order confirmation page. Moreover, a King size mattress by definition is 78/72 inches (6.5 / 6 feet), which is what i was expecting when i placed the order. However, when i got the mattress, the size was 72/70 inches, which is a non-standard mattress size, and NOT a King Size. On contacting [protected]@paytm.com, i received a response that a product return cannot be processed as i've received what i ordered. Which is clearly wrong and misleading on behalf of paytm.com. The mattress is in its original packing. On calling paytm, the representative repeatedly asks to contact via the email, while i'm not getting any sensible response from [protected]@paytm.com