Paytm — Not providing cashback offer on promocode that i applied against order no [protected]

Address:	Pune, Maharashtra
Website:	www.paytm.com

Hello, I have ordered e-O Adult Cat Food Chicken Veg 7 Kg on 22 sept 2015 with coupon code "Pet30".(PFA products page on which promocode is already given) The promocode offer was to provide 30% cashback in paytm wallet. I did not receive any cashbak from paytm, i opened ticket with paytm regarding my cashback complaint. But paytm is saying i have not applied any promocode against my order. When the promocode is provided on products page itself and if we click on appplu on products page, promocode automatically gets applied to order. So in my case i remember that i have applied the promocode and re-verified too that promocode is applied. Paytm is not processing my cashback against the offer that paytm itself has published. What proof am i supposed to give paytm to show them that i have applied promocode while giving order? Am i supposed to record every session while i place order with paytm?If so, please they should inform publicly. Please help me get the offer benefit of promocode that i have applied against order no [protected] on paytm.com