Rediff Shopping — Not refunded my money after returning the product

Address: 560066

Website: shopping.rediff.com

Ordernumber 12354023 order number.
I have purchased from rediff shopping using citibank account the details of Order# 12354023, 10400mah Universal Aluminum Metal Portable Battery USB Power Bank Charger on 28th September 2015 as it was a duplicate product i returned the product and asked for refund they said they have refund the amount and check with citibank but citibank said they have not recieved any refund from rediff .They said they will give the refund now and investigate the case they gave me the amount of 437 on Nov 3rd 2015 from citibank and later 5TH Jan 2016 they had taken back the amount from my account AS they got the confirmation from rediff shopping they have recieved the amount. now rediff is claiming citibank is holding my amount and they have already refunded and chargeback has taken place and now citibank is not responding anything all the proof mails from rediff has already shared with citibank i want my money back.