Unfairly declining of a application for finance

I app**** for the vehicle finance through a dealer and my application was declined because of the following reasons:Credit conduct, Excessive exposure with retailers and banks, I've got no accounts in arrears, no defaults and no judgments but my application for vehicle finance got declined because of the above,I feel that my application for vehicle finance was unfairly declined as stated by the National Credit Act and i would appreciate it if you would reconsider my application, upon receiving the above message i emailed WesBank and was told that I`ve got a low credit score, how can I have a low credit score but there is no adverse information on my credit report