Bad customer service

Morning. On the 04 January 2019 I got a installment of R505.05 to be payed on the 28 of January 2019. I payed R1212.64 on 05 of January,but still on Monday 07 January I got a sms from Barrett & Associates saying I have a amount outstanding and that my credit card has been handed over. On the 08 of Jauary I phoned ********** . The lady on the other side told me that she cant see any problem with my card,but she told me that she will put me through to the card collection department. I could not get hold of anybody there,so I phoned Barrett & Associates and spoke to Charity. She told me that I must pay the R505.05. I told her that I did make the payment. She then told me that I must not worry. Now my credit record looks bad and I had to go through all this **** for no reason. What I want to know is I haven't even been with fnb for 6 months,and am I looking at a bumpy road further in the future where if you pay before you should pay and also pay more than the amount due,is this then the type of service I will get??? My I.D number is ********** 046086 Mr R.W Strydom. Barrett & Associates Ref Number:FNBC150975