Standard bank Vehicle and Assets finance

I do not thik that standard bank value their customers, everytime I apply for a loan from standard bank they dissapoint me. they either decline my application or give me a ridiculous interest rate, today I app**** for car finance they provisionaly aproved and when the consultant called me I was chocked when he told me that my intersest will be over 19% I asked him repeatedly If he was saying 9% but he said he is not mistaken. I now wonder what did I do wrong to standard bank because I had financed my car through standard bank and the rate was negotiated by a Dealer may be they do not like their customers to negotiate with them, the dealer negitiated prime + 3% they are giving me prime + 9 . and my credit score is more than 660. I wonder how people get low interest rates with them.