Disputed transaction in ABN AMRO credit card

I have a credit card of ABN AMRO BANK.

There is a transaction of amount Rs. 2494.55 in my statement of Nov'08 which was not done by me. The merchant shown on the statement was TATA INDICOM PAYMENT MUMBAI. I reported the dispute with the ABN's customer care, they sent me a form and was said to send the filled up form back. I did the same. I called up several times after that but they told me that the issue is under investigation. I called few days back again and I was told that the transaction was an internet transaction and used my CVV number so I a liable to pay the amount.

I was deciding what to do next, I received my February's statement and surprinsingly there is again a similar transaction(same merchant) and this time the amount is Rs.3000.

I have sent 4th level escallation (as per the bank's site) emails about my issues and seeking for waiving off the disputed amount, but I got the reply that I need to make the payment, and suggested me as per the following statement:

"Under these circumstances the Bank would not be able to raise a charge dispute for the transactions and we would request you to raise the issue with the site/ merchant directly. "

I do not know how to raise the issue or also please suggest me some way to handle the issue.