HDFC Bank — Credit Card - Amazon Pay Voucher Not Received

I had applied for the credit card on 20/01/2020 under the offer 'Complimentary Amazon Vouchers of Rs.1500'. I activated the the credit card on 29/02/2020 and made the first transaction on 01/03/2020. It has already been 3 months since, and I haven't received the vouchers yet.

The customer care told me that I am not eligible for the reward (without showing me any proof of it whatsoever) despite me having applied through the same offer mailer.

I have also submitted the proofs of the same, and I'm attaching them with this email for your reference.

I have been a dedicated customer of HDFC. Hence I request you to issue me the vouchers at the earliest.