Bad customer service by Standard Bank ***** Line

I bank with Standard Bank. Today I noted that on 7 June my credit card was debited an amount of 1 912.32. I did not use the card for such a transaction and thus I quickly called Standard Bank ***** line for assistance. I am very disappointed in the manner in which I was treated. The agent indicated that he would ask me security questions and according to my knowledge I answered all the questions and yet he said the system says I am lying. I indicated to him that well that the questions pertain to matters that I would have first-hand knowledge. He indicated that because I have failed to provide him with the right answers he was not going to help me. I am really angry at the manner in which I have been treated. I was not assisted on the issue that made me to call in the first place. Somebody used my credit card facility without my knowledge and Standard Bank could not be bothered since according to them I had failed to answer security questions correctly.