PayTM - Promised Cashback not paid

I purchased a laptop from HP where PayTM was offering **% cashback on *th Oct. Just to be sure, I separately wrote to PayTM Customer care asking them to check the order and confirm if I am eligible for Cashback against this order or not. They confirmed on *th Oct (email attached), that I will get cashback in ** days against my Order ID. Basis their confirmation, I concluded the purchase and waited for the cashback. I only purchased this laptop because of the cashback promised else I could have bought it in less price from elsewhere, but since they confirmed that I will get the cash back, I didn't cancelled the order. Now even after * months, they are not paying the cashback & giving me different excuses. Please help me ask PayTM to honor their commitment made from their official mail ID.