Paytm Mall - Wrong commitment done

I ordered an iPad *.*-inch *th generation from paytm mall on **th March. Wherein at the time of placing the order, I applied promo code "PATYMFIRST" terms of which I have attached a copy. It clearly mentions benefits of lump sum amount of Rs.**** but later I was intimidated that same would be disbursed bifurcated over a time span of * year & that too on my spending which wasn't mentioned anywhere. When I called them regarding same they denied my claim vehemently.
Secondly, when I checked my box after a day, I found that its charger was missing. On filing complain regarding the same, they first promised to replace but later on denied that too.