very bad service

Bought chips and found them to be stale so returned them hoping to get fresh ones only tone rudely asked why I ate them if they were stale and also told how people like to buy and eat then want to return what was bought. I tried to explain that I did indeed start eating but could taste that they were stale but again the lady was very rude so I asked to speak to the manager but I was told the manager does not want t? be bothered.they then gave me back he R30 back while shouting implying that I was trying to get a free meal. Will never go there and will tell everyone I know