Amazon India — cash back not received icici

Amazon india offered a cash back offer for the purchase done during during 18th - 24th oct & the promo was great indian festival. The offer was to get an extra cash back of 10% if the purchase is more than 50000.00 with icici card. And they were supposed to give the credit for cash back by 3rd week of jan19. I have been following up with amazon from last 1 month to get my cashback but every time i talk to their customer care, i get the same response that they have escalated the issue & a form has been filled. When i asked for complaint no. They refused to give the complaint no. Also. Every time a new person come online and then they want me to narrate the entire story once again. And they have accepted that i am eligible for cashback but still i am not getting the refund. This is the way they are cheating their customer by giving false promises.