Reliance Trends — paytm cash back vouchers not received

Address:

Ernakulam, Kerala, 682017

Dear team,

This is to inform you that i had made a purchase at reliance trends at karunagapally, kerala on 2/11/2018. The main reason for the same is that there was an offer on paytm in which a payment of 1500/- or more through paytm will fetch you 1500/- cash back vouchers in paytm mall.
Bill details:
Payment ref no:[protected]
Tax invoice: [protected]
But as of now i haven't received any cash back voucher in paytm.
Attached is the offer displayed at the store.
I had informed the paytm and reliance customer care, but they are simply cheating with automated messages.