Manager swore at client in front of 6 year old son

We went to Pic n Pay Princess Crossing on the 29-08-2015 to get some goodies for the weekend. Then the Promoter for \Sticky"informed me that if i buy a party pack of \""chomps\"" I will get a \""Sticky\"" for free with it. At the Till the when i asked for the \""Sticky\"" The cashier said that the Chomps does not count as part of the promotion. The \""Sticky\"" Promoter walked past and confirmed that the Chomps is part of the promotion. Then they called the manager who went to go and look on the shelf and came back and said its not part of the promotion. She started arguing with me and when a friend intervened she started screaming and swearing she is not our child. In from of my son after she made him cry. We asked her is she was happy with the situation and she basically asked us to leave the store. After witch we left all our shopping on the counter and walked out. I would like a written apology from Margret(The manager) and i expect the \""Sticky\"" for my son. Furthermore I will never set foot in that store again as this is not the first time we have had issues with bad attitude and rudeness from the staff. """