Unacceptable behaviour

Today I experienced an incident that I wish never happens to anyone else. Therefore, I feel the need to address the problem. My mother, sister, domestic worker (who has been with us for more than 10 years) and myself appoached the check in counter where I was abruptly asked what my name was. After which the lady at the check in turned to our domestic worker and asked what her name was. First she asked this in Xhosa and then realized that our domestic worker was Zulu. Our domestic worker was startled as she didn't know what was happening as she hasn't flown before. The lady at the check in counter repeatedly asked her what her was. My mother then handed her all the ID's and explained that our domestic worker was with us. She then went on to scream all our names from the screen and laughed at the way she pronounced them. I was outraged at the way she treated the domestic help and ourselves, but kept my cool. She then went on to imply that we treat our domestic worker as a ‘slave’. She did this because my sister and the domestic worker picked up one of the bags. In Zulu she told her 'you shouldn't be picking up heavy things.' My mother then went on to explain to her that our domestic worker has been with us for over 10 years, she is part of our family and treated extremely well. My mother did not even have to explain herself. The lady then began to sing loudly. Her behavior was just extremely unprofessional and unacceptable. In my experience when you go to the check-in counter all you are asked is your destination and for your ID. This situation needs to be addressed and taken seriously.