Money stuck in between CitiBank and BookMyShow

I have done a transaction where i had booked a movie ticket with BookMyShow of 366.00Rs on 19/06/2016. The amount was deducted from my CitiBank account but the ticket was cancelled due to internet issue the same day i called BookMyShow and asked for refund they said they will do it within 10 days. After these 10 days still the money was not credited to my account i called BookMyShow for the same and they said that the money has already been credited and when i sent them the screen shots they gave me a reference number and said to talk to CitiBank and when i called the citibank they say the money has not come at all. its been 18 days i have lost over 100+ rupees by calling both of them. Please suggest how to lodge a complain on CitiBank and BookMyShow as they have crossed their 10 days response limit. I want to sue them and get my ticket money and as well as my mobile currency also. Also plese suggest me where and how as i have no idea on law. I really want to sue them for a bigger amount as both of them have crossed their limit.