HDFC Bank — cashback not received for purchase of iphone from aptronix, hyderabad.

I had purchased an iphone 11 at aptronix sarath capital city, hyderabd through hdfc debit card bearing invoice no. Sccti/1920/739, invoice date[protected] for which i am entitled to receive a cashback of 6000 within 120 days from hdfc as per the offer mentioned from the date of purchase but its been 6 months i haven't received any cashback from hdfc. Please rectify the issue at the earliest.