Disappointing interest rate.

I am really disappointed with Nedbank MFC. They are failing to lower my interest to atleast 15%. Their reason is that I don’t have enough credit, they are failing to lower the rate by 0.50. Really they rather lose the deal. I have been with Nedbank for more than two years. I took a personal loan with them paid it in less than a year. I took a credit card last year November and I haven’t fallen behind with it. Tell me what credit I don’t that they can’t give me 0.50.