Bad Service from Staff and Manager

I visited the store last night around 19h35 after gym to do my shopping , I finished doing the shopping around 19h45 stood on the queue to pay until it was around 19h58, on my shopping there was a bottle of wine , the cashier (Nomkhosi) refused to sell me the wine as she was saying that they only sell wine before 19h00 I tried explaining that I have been on the queue to pay before 20h00 and she still refused and said it was against the law and giving me attitude

I then nicely asked the lady to call the manager (THOBILE) about this issue , the manager took about 4min co come out of the office . The cashier explained to her and I tried explaining that we have been there waiting to pay before 20h00 , With a stinking attitude the only words the manager said to the cahier was DO NOT SELL THAT WINE and she went back to the office without saying a word to me, I then asked for their names as they did not have the name badges on and no one was willing to give the names to me , until I asked from the other cashier who was next the till point,

I am also in customer service and I would not allow such bad service from anyone as I do not give my customers bad service , please look into this otherwise you have one customer to loose ,

Thank you