Poorvika Mobiles — cash back not received for mobile purchase

Address:

100 Feet Road, Coimbatore, Coimbatore, Tamil Nadu, 641012

Purchased the Samsung J6 model mobile from Poorviks mobiles, 100 feet road on 14.01.2019. 10% cash back offered while swiping credit card, Citibank and it will be credited within 90 days. The cash back amount around Rs. 1200 is not received in my account even after 150 days. Approached the show room but there is no firm response till date.