Unfair treatment

i have been ABSA client since i bought my first car in 2014, i have been applying for vehicle finance and got declined due to my credit score. but recently my credit score has improved i am on GOOD according to the Compuscan/Transunion but still i am being declined because 8 Months ago i had one month arrear on my vehicle account. it was only 1 Month but ABSA is using it against me, where is the fairness? i have been a client since 2014 but seemingly ABSA is looking for mere reasons not to grant credit. previously their excuse was my credit score which i understood, now that my credit score is good they are telling me about the arrear amount of 1 MONTH that was paid 8 Months ago. this is very much unfair.