Amazon India — cash back offer-order #[protected]

I have placed an order on dt.23/09/2017 vide order #[protected] on payment of amount rs.17409.00 through my credit card ending with 4742 and said product of the order was received by me, in that time amazon offer to discount 10% cash back on visa card payment through on debit/credit cards which was credited to card account on or after 23rd december 2017, since 23rd december 2017 i have inform amazon through email regarding cash back offer several times i. E. 100 and above emails till today but they avoid the offer mentioned your card is not eligible for that offer saying that my card is corporate card, but i have possessed a individual credit card name & style "business regalia first ending with 4742" which was also informed them severally. It is also informed to amazon that credit card ending with 4742 is not a corporate card which is informed by the concerned hdfc bank (Attached a copy of the screen shot of email confirmed credit card ending with 4742 is not a corporate card)