Amazon India — cheated by amazon india and didn't receive cash back as promised even after 2 month of promise date

I, Zuber Shaikh with Mobile No (XXXXXX0033) have Amazon account since 2014.
Recently There was “The great Indian festival 2019” offer from Amazon India from 29th Sep to 04th Oct 2019.
Terms & Condition: 10% discount on sum of all order’s amount during the sale period if total amount is 50, 000/- with 2, 000 instant discount and remaining as cashback in my SBI card account by 5th Jan 2020.

During the sale, I ordered multiple items with order Id's[protected],[protected],[protected] and[protected] amounting to Rs. 68802/-
I have received the Instant discount of Rs. 2, 000/-. However, I am yet to receive the remaining cashback from Amazon India even after 2 month of the promised date.

Immediately after the sale ended, I called Amazon customer care to confirm about my eligibility for remaining cashback other than instant discount. The customer care executive informed me that, I am eligible for the remaining cashback and assured that the cashback will be credited to my card account by 5th Jan 2020. Till today i.e. 03rd May 2020, I haven’t received any cashback.
I have been following up with Amazon almost every 2 weeks and every time I am said that I am eligible for the cashback and I should receive it in next few days. I have all the proofs from amazon regarding my eligibility.
I even received an email last time from amazon stating Amazon is going to process my cashback between 14-Feb-2020 to 18-Feb-2020, but even that turned out to be fake commitment.
I think, I have been cheated by Amazon India and they are just pushing days by giving false assurance, that I will be getting the cashback in few days.

I have all the conversation saved and email as well that I can share.

Thanks
Zuber Shaikh
XXXXXX0033