Bajaj Finserv — Cashback not received even after 5 successful emi payment

I have purchased my Samsung phone through Bajaj emi digital store through Bajaj Finserv app. There was offer listed which says that after paying first 3 emi payment cashback of Rs 1000/- with be paid. I carefully entered the promo code of that offer & then follow the procedure to complete the transaction. Order was completed & phone was delivered. But even after 5 successful emi payments, no cashback is provided. This is clearly cheating/fraud. This is unacceptable. Provide me the applet authority contact number or should I have to file complaint to Consume Forum?