HDFC Bank — hdfc bank - sony sl-eg5 480gb typec usb 3.1 external solid state drive (black) cashback not received

Address: 1/2 Central Park, Premises No 98, Raja SC Mallick Rd, Kajipara, Kolkata, West Bengal 700032

I bought a sony sl-eg5 480gb typec usb 3.1 external solid state drive (Black) from amazon by using my hdfc debit card on 8th october, 2019. The order no is[protected]. There was an offer of getting cashback. But till now i did not receive any cashback amount after almost 8 months.
So please do the needful.