Flipkart — non refund of cash back offer

Address:

Mumbai City, Maharashtra

Sir i have purchased and ordered redmi note 7s on 12 aug 19. Item delivered vide invoice no. Od[protected] dated 15 aug 19. During flipkart given a offer of rs 500/- rupees when u pay with hdfc debit card. I have paid rs. 11999/- by using hdfc debit card. Till now flipkart not refunded rs. 500/- as they shown in during order. Ihave contacted flipkart customer care but there are not able to reply