A cashier at TOPS in Belhar shouted and mistreated a customer

On Wednesday (9th June 2021) I went to TOPS, Erica drive, Belhar, Western Cape between 15h00 and 16h00. As usual I grabbed my drinks and went to the pay, then a regular cashier indicated that I could go and pay by her till which I did. While I was by the till I asked for two boxes of cigarettes (20 Peter Stuyvesant and 20 Marlboro). By the time I told the cashier (the name will be provided on request) who was helping me that I needed the cigarettes as mentioned above, the cashier was asking me to buy her a certain 6 pack of drinks that is on special that comes with two complementary glasses which I refused to buy for her. She then fetched the cigarettes, scanned the drinks and the cigarettes. I then noticed that she gave me 10 Peter Stuyvesant and that time I already paid using my card. I then notified her that I specifically asked for a 20 Peter Stuyvesant box no the 10 Peter Stuyvesant box (The other cashiers witnessed me saying that). She told me there was nothing she could do and not admitting that she was n`t attentively listening as she was busy asking me for a tip which was in a form of a 6 pack of drinks that comes with glasses. She insisted that she can sell me another 10 Peter Stuyvesant box to make it but I was using a card and I informed her that my bank will still charge me transaction fees for buying 10 Peter Stuyvesant box for R21, which is resulting from her mistake. She started shouting at me in front of customers and her colleagues. She never showed any remorse and she told me I can go inside Spar and speak to the manager and the cashier did show that she does not care. I am really disappointed with the service and I would like to know, as customers do we have to tip cashiers at TOPS? Is it part of SPAR`s code of conduct for employees to insult and shout at customers? Can this matter be investigated, as a loyal customer the treatment I received yesterday was and will never be acceptable. With no doubt, it is notable that the cashier probably didn't receive sufficient training on customer services (if received any training at all) or the customer lacks cashier relation skills and therefore such cashier who asks for tips (buying them drinks) from customers, who does not respect customers and who shout at customers should not be working with customers.