Credit Score affected because of Nedbank

I'm really disappointed with Nedbank. When I checked my credit score beginning of this month it showed me that I've missed a payment on my Nedbank credit card for February. I've never missed a payment on my credit card what just happened is I changed jobs and my payment date changed from the 25th to the 27th. I informed Nedbank in time and told them I've changed jobs I need to set up a debit order of a R1000 for the 27th of each month. This is affecting my credit history and I sent them an email a week ago and no one bothered to call me.