Paytm Mall - Assured cash back not credited

I purchased a laptop from Paytm mall in November (Order No. **********). Paytm offered benefits worth Rs.**** in the form of cashback vouchers,along with the purchase as a part of their Diwali sales promotion. These benefits included cashback on purchase of laptop bag, grocery items, flight ticket& on mobile recharge. My purchase decision was influenced by this offer provided by Paytm. After the purchase, I received several coupon codes to be applied to avail the cashback.However, some of the promo codes did not work. So, I contacted Paytm customer support , but they did not provide a satisfactory solution(Complaint reference no: ********) After repeated attempts, I decided to contact their social media team. I contacted them on facebook. After following up for over a month, they finally gave a resolution and agreed that they will manually add the promised cashback to my account. So I went ahead with my purchase.But after placing, they are refusing to provide the cashback. Out of the total promised cashback of Rs.**** ( Rs**** on grocery items+ Rs, **** on laptop bag), only Rs.*** has been credited to my account. I have screenshots of the entire conversation I had with Paytm. I'd like to raise a complaint against Paytm for wasting my time & for not crediting the promised cashback. I am attaching a transcript of the Facebook chat I had with Paytm, in pdf format as a proof.