bad customer service

I have been a loyal absa client from 2012 to 2015 paying my car installment every month. In 2015 i changed jobs in the middle of the month therefore i didn't get paid as per normal and missed the payment however made arrangements with absa to pay a few days later however absa still put this against my ITC making it difficult for me to enter into certain contracts as i get declined. This is not treatin customers fairly. I feel like absa is not loyal to me as a customer at that point in time.if this is how absa treats iys customers im very shocked and appalled.