Amazon India — non refund of 5% cash back amount with purchase with hdfc card offer

Address:	Nagpur, Maharashtra, 440001
Website:	Amazon

Not received the refund amount of 5% with use of hdfc card as per the offer.
I have purchased on 26th September order no[protected]..
Confirm the details why not received yet.
Why not been refunded till date
Tried to contact customer care but unable to reach.
Payment details shown before making the payments and details abt refund but not received anything to date