Waiting for 30mins to pay with voucher

I got a mobile voucher of R50 from C*****, went to PNP Cape Gate and when I got to the till the cashier did not know how to enter the voucher.She called the manager (a white male not sure of his name) and he simply said he has no idea and left again. The guy packing the bags then took my phone with the code to another cashier and she also didn't know what to do. He then took me to information with the goods I wanted to purchase and told Michelle to help me. She responded by saying that she is busy helping customers and I must wait in line. He then told her that I already waited in line and she just ignored him and me. I asked him to call the manager who never showed up. After helping the other customers Michelle finally helped me and told me the code is not working. She then proceeded to help other customers and once again ignored me. She didn't once address me in a formal manner or anything. I then went to find a manager myself. It turned out to be the liquor store manager and she then realised she needed to ring up the goods first then type in the code. She then told me she thought I wanted to draw the money, even though she read the sms from c***** herself!