HDFC Bank — Cashback not received

Hi,

I have a hdfc credit card and had purchaed a jio broadband subscriptions worth 6000 rs where the offer stated that i would recieve a 10% cashback if i used hdfc credit card.. I had purchased the subscription in dec 2019, but still have not recieved the cashback of 600 rs.. Its been 180 days since..

Please solve it immediately as rs 600 is also very valuable to me as i am paying loans to hdfc credit card..