Different races different treatment

My wife and I went to Woolworths Benmore on Saturday to do some shopping and we decided to get a coffee afterwards. The cashier was amazing, and because there was no water we were directed from the wcafe to the inside coffee station. We went back in and asked the cashier politely for our order and were treated to eye rolls and abrupt responses while the cashier kept talking to other staff while we were trying to order. She realised we were upset and just kept looking at us with disdain and the eye rolls continued. My wife is Indian and I am coloured. Another white customer ordered and she was treated with smiles and really great customer service and respect we did not get from this same person. Of course the customer was not at fault she was just being a decent and friendly human being. The manager was not available but I can assure you that we will not go back to this Woolworths until we get a satisfactory response from the management. I will also be using my social channels to highlight this treatment. We live in Sandton and often frequent this Woolworths alongside grayston and Sandton and this is the first time we have received such service. I am appalled that in this day and age we get this kind of treatment, which is clearly ******.