Citi Bank — Fraudulent transaction but Citi Bank does not want to resolve

Website:

www.online.citibank.co.in

Without even receiving any OTP there was one transaction on my Citi Bank cr. card and the amount of Rs. 380 was debited. Even though I raised a complaint with Citi Bank against the merchant who doesn't have any email id, contact details nor I know as to what kind of products/ services they are into, Citi Bank management has not bothered to properly investigate and said that I did transact and had to pay the amount.
How will I be able to enter an OTP without even receiving one and I feel that Citi Bank seems to have some tie-up with the merchant so that such transactions would be able to go through without entering the OTP.
Also, even though I blocked the card, Citi Bank sent me an SMS and email stating that the card is active and I can use it. This obviously gives an impression that blocking of the card is just an eye wash but eventually Citi Bank wants me to use the card (I have not only blocked it but also cut it into pieces and thrashed it) but still Citi Bank would say that I have used it for transacting with some merchant and perhaps that is why they are insisting that I start using the card again.
Also, in the name of waiting off the additional amount that gets deducted by using the card in certain IOCL petrol stations, Citi Bank seems to not provide the credit in some of the transactions. For example, when I used the card at the same petrol pump on the same machine to swipe the card on 5 different times for Rs. 200 each time, I was charged Rs. 2.36 additional charges and 3 times only I was given the credit but 2 times I was not given the credit.
Already the price of petrol is too expensive and now Citi Bank is charging extra by asking the customers to swipe their card and on one hand say that they would refund the extra amount but on the other hand they really do not give the credit.
I have called Citi Bank customer care as well as sent several emails including to the Principal Nodal Officer of Citi Bank but I am given a feeling that the senior management is only interested to get their salaries and not wanting to listen to and resolve any of the customers problems. It is so sad that our Govt. is allowing such private banks to be in operation in India which in turn is trying to cheat the customers like me in order to earn a lot of money, especially the senior management who, instead of resolving the issues are trying to see to that they get their salaries and want to feel happy at the end of the day. It is a pity that this bank staff are cheating and harassing the customers in this manner.