[Resolved]  Cleartrip — Fraud Amex card coupon ad on Website

Address:

Bangalore, Karnataka

I booked one return ticket from bangalore to chandigarh for 29th june using cleartrip.There was an ad coming on the website that if you have an American Express Card,you can redeem the coupon for an instant 1000 Rs cashback.I used that coupon code but after I filled in the card details,it showed an error in the coupon code reading "Sorry,we couldn't apply the coupon code" and booked my ticket at undiscounted price without even prompting to ask me that whether I want to continue with the payment without the coupon code or not.
I called their customer care but the excuse they are givng is that their IT team has told them that no coupon code was used from my side,so they can't give me the cashback. Although,I have the screenshot for the error message that came at the time of booking.Still they are not ready to accept their fault and give me the cashback .

Below attached is the screenshot for the error message.