Standard bank vehicle financing

My vehicle is financed by standard bank. Every month my car goes off by the 29th. At the end of March my car was only debited on the 31st. I went on to my credit score and standard bank marked it as a missed payment. How on eart is it possible????? Due to standard bank that had a system issue now I need to have bad credit score due to there negligence ????? This is not on. I spoke to a lady and she said ,agh it will be cleared by 3months . Really 3 months? I was in the process to change from Nedbank to Standard bank ,but after this I won't. My husband is banking with Standard bank ,but soon Standard bank will lose another faithful client!!!!!