Inconvinienced by two cards while I was not aware

I ordered a new card as I misplaced an old cheque card. Southgate branch issued me with a new card without without cancelling the old one. on the 01/10/2015 when i realized that my credit card is being used, I went online and cancelled a platinum card but only to find out that by then I cancelled one of the cheque card that was left active without my permission. On the 30/12/2015 a credit card that I was under the impression that it was cancelled it was then used to withdraw cash from my cheque account , R5000 was withdrawn. I then called the call centre and that is when i learned that I did not cancel the card. I went to Northgate branch and I was further showed that on the 01/10/2015 a cheque card was cancelled but not a credit card. I spoke to Muller whom gave me an impression that they are not will to take responsibility for this as a branch. I got a response from her but it was regarding that i can link my cards. this is not what I asked I asked why were they 2 cards on one account which I feel that it has inconvenienced me. Because if I only had two cards a credit card and a cheque i would have known the following day that I cancelled a wrong card. Can FNB take responsibility