The Chennai Mobiles — Cashback not received

Address:	No.8, Medavakkam Main Rd, opp. Bharat Petrol Bunk, Puzhuthivakkam, Chennai 600091
Website:	www.thechennaimobiles.com

I purchased iphone 11 at the chennai mobiles on 8th dec 2019 and i was promised rs.6000 cashback within 90 days. I have still not received the cashback on my account (Paid using hdfc debit card) and the showroom where i bought the phone also not giving proper response (Chennai mobiles, ullagaram branch)