standard bank did not want to help with complaint

I wrote a complaint about standard bank. I was aware of the extra amount I had to pay but not the increase in percentage. Later I went back cause it dawned on me why am I paying R700 extra on my installments just for an extra R3000. I was told that the interest on my loan was now an extra +_ 7 percent that's why. If I had know that I would not have signed and I think a good personal banker would make sure to tell me that its not worth it to take and extra R3000 if its going to increase by +-7 percent. Any when I went back they gave me a few days to pay the money back and my interest rate will return to +- 15 percent thank you Standard bank. It was not enough time for me so I could not pay the money back. case was investigated but was told they can't help me. This week I got a consolidation loan from Old mutual and after I signed the consultants manager went through the contract with to make sure I understood everything. If Standard bank did this with me I would have know about the percentage. If Old mutual did this with me why did Standard bank not do this. We talking about R1000 loan which is a big purchase. I would of understood everything and what about my consumer protection