Citibank — Refund amount not reflecting in my account

Address:

Bangalore

My name is Anjana C T and I have 4 refunds initiated by Amazon to my citibank account on 6th of Nov for an amount of Rs.2649.
Amazon initiated the amount to my card but I still have not got the money. Amazon sent this reference number 598364
and told me to follow up with CITIBANK. Bank is telling me they need a 23 digit ARN number which Amazon is saying they do not have. I have been making calls everyday since 11th Nov to Amazon and CITIBANK for help but with no solution yet. So
please kindly respond to this complaint it's very urgent. I have registered the same complaint in the name of Amazon as well as i do not know the issue is on which side
Thanks you sir