Horrible altercation with shop assistant

On 1 August 2017, I went to a Donna Claire store in The Grove, Pretoria, to receive the most appalling customer service. I was standing in line while two shop assistants were helping another customer (stood for about 5 minutes). The customer wanted to return an item but his slip was torn. He had bought the item for his wife in the Donna-Claire Menlyn branch and the assistants were explaining to him that they cannot take the item since the slip was torn, they couldn't see the bar code, it was a sale item and it was not bought in their store so they couldn't help him. There was a big argument between the three of them and they even had to call the Menlyn branch in efforts to assist the man. All this is happening while I am standing in line. Within 15 minutes of me seeing that the argument wouldn't end, I decided to call my mom who also heard the argument between the customer and the staff and was also surprised. While on the call, the other assistant decided to leave the argument and assist the other customers. I was next in line (still on a call with my mom) to which the lady shouted "NEXT!! I do not assist people who are on the phone!!" And thats how the fight started. We exchanged words for a good 20 minutes. She went on about how rude it is to answer the phone while Im being assisted and I should learn some manners and how tired she is of rude customers. I also gave my opinions of her poor customer service and soon the other customer soon joined in and it was a full on screaming match between her and the customers. There was a lot of dissatisfaction. The bottom line is, they shouldn't have kept us waiting while assisting one customer, even if I was on the call, I have every right to be whether or not the service was slow-she has no right to tell me I'm rude. Thirdly, one doesn't have a full on argument with a customer the way she did with me. And after all that, she couldn't even bring herself to apologize even when her colleague told her countless times to calm down. The name of the assistant is Mohau at The Grove Mall in Pretoria. Donna-Claire Menlyn can verify this as they were on a call with them while the customer vs staff war was happening and she wasn't even cognizant of that. I thought I had gotten over it, but I passed by the store on Saturday and got angry all over again and couldn't get myself to go in. I live and shop around The Grove area but I would rather go to Donna-Claire Wonderboom because the service there is excellent!!