Amazon India — Cashback not received

Address:

Indore, Madhya Pradesh, 452001

Hello Sir/Madam,
I have ordered two mobiles on 11th August 2015 in the Amazon Great Indian Freedom sale. As per terms and conditions, I can get Cashback of 15% by using HDFC debit card on delivery.
Link for the offer details- http://www.amazon.in/b?ie=UTF8&node=[protected]
My order amount is Rs. 12728, order Number[protected]. As per the offer, I was eligible for the cashback of Rs. 1500 on my transaction, to be credited before 12th november, 2015, but i have not still received the cash back.
I have contacted them so many times, but they always try to ignore my complaint, their representative always says me to wait for 48 hours.
I am mentally harassed by the Amazon customer care.
So please, look into the above issue and oblige me.
Thanking You!