Breach of Account

I currently owe payments on my Standard Bank Credit Card. I can't commit to the total repayment value so I made arrangements of R100 per month. On the 03 March 2015 Standard Bank did a transfer of R1500 from my PureSave account to my Credit Card without my knowledge of this, I was not informed! I realised some funds were short and noticed what the bank did by checking my online statement. I still await a response from the bank... This is absolutely unacceptable and a huge violation of rights!