Citibank — Not received refund amount into my account

Address:	Chennai, Tamil Nadu, 600002
Website:	www.citibank.co.in

Hi Sir/Madam
I have purchased some products in myntra. And i have returned few items in that. They have collected the items from me and initiated refund transactions. In myntra account it says that they have refunded successfully but i did not receive the amount in my bank account. So i have called up Citibank and enquired about this, they have asked me for ARN numbers so that they can track. I have got the ARN numbers from myntra and provided the same to Citibank. But bank people are saying they have not received any refunds and not able to find these ARN numbers in their system.
I am not sure why they are not able to find these ARN numbers. Please help me in resolving this issue.

Here are the details:

Order number[protected].

Return No: 18180292
Return No: 18047463

ARN : 75134836303316086304286 - Amount Rs.713.57 - 28th Oct 16
ARN : 75134836308816090013943 - Amount Rs.630.97 - 2nd Nov 16