Credit application declined

when I was still a student I had credit card and some few accounts which I was paying well with my stipend from the Department of Roads and Transport, when my contract expired I was struggling to pay all my accounts but I managed to pay some though I was no longer working, after 7 months I got a job and the first thing I did with my first salary was paying my debts, I paid all my debts that was over a year ago, but until to date Standard Bank has been refusing to finance me when I want to buy a car, even a loan is declined, this is unfair because my record ever since I got a job has been very well, my accounts are paid on time and I even have a car which was financed by ABSA, but now I want to trade it in and Standard Bank is still refusing me credit ,this is unfair and I appeal to Standard Bank to reconsider my applications. You can't continue treating me like this even after 14 Months of settlement of my accounts.