No Customer service/ Bad attitude

On Saturday, as every month I went to Dis-Chem to collect some medicine. Upon my arrival two ladies was at the self help counter. I greeted them, and started placing my order with the one lady, that just out of all the items gave me one product and blatantly just ignored me. I said to her, I'm not done yet, and she just carry on ignoring me. I though it was a joke, but than behind me a gentleman showed up and she assist him with smiles, and just acted like if I'm not standing there. I said to her, excuse me, how can you carry on helping someone else, when I still require service. Again her response was abrupt, I spoke to her colleague that also had a \don't care attitude". I asked them where is the manager"