Shoprite cashiers being ******

At Shoprite Pretoria North you get good service and prices over. But today was the second time we were very unhappy with one of they're cashiers. It is a lady who's till is open then when she sees a white person standing in the que to pay she puts up the clised board as soon as she sees you leave and go to another till she opens again this happend the second time with me and also while waiting at another till again when another young man stood in her que she closed the till until he left. If that is the way people are being treated there I'd rather go a block futher and go where everyone is friendly and professional.