Business plan, make less profit.

I proposed a car purchase through Wesbank, they ripped me off on my first purchase charging me a 13% interest rate, when I wanted to purchase a nother car they tried it again, eventually coming down to 12.5% on the next car but that was still unaffordable, surely if you bring the one rate down by one percent to gain a new deal that would make more sense. But Wesbank beleives charging me 3 percent above prime is better than 5 percent. Wow, that must be higher grade maths.