Requested ca disc still not received because of NFC's finger error

I received an sms that I needed to pay R1 168.55 in order for my car license disc and send the proof of payment to ***.z. I did that and I requested Dimakatso to send my disc which has expired. Dimakatso sent me an email stating that I need to pay extra amount. I argued that I only was informed about R1 168.55 which I paid now when I request my car license disc and they know that I need it the tell me I must pay extra amount of R532 and some cents. I asked them who job it is to inform clients she said it's a finger error and I must understand that "we are all human beings we all make mistakes"I asked her if I were not to pay my monthly car installment and say there is a" finger error" where they going to understand that we are all human and that we make mistakes. I asked them to fix their mistake. I cannot suffer because of their mistake from their system. She told me that we all new about VAT. I emailed a gentleman Ridhwaanah who also works there and who sent me the sms that I needed to pay R1 168.55 because my disc is available. He also said I must understand its a mistake they were not going to change their protocol for me. I asked them is that how they treat their customers that if there is a finger error on their system which I don't even know about then I must suffer and not get my car disc up until now I have not received my car disc. I even asked them can't they carry it over for the next month because I did not know about this that when I got Ridhwaanah'response. I am very disappointed. I once asked they if I wanted to settle the car how will it be. Dimakatso has not responded to my email regarding that. I'm really disappointed. If you can help me please.