Rudeness and bad treatment of customers

I purchased incorrect parts for my car at Ace s****yard in Springs on the 30th of November 2021, the security guard was not happy as he wanted me to be charged more he even asked the person helping me a question as to why they sold the parts cheaper, when I went to return the parts on the 1st of December 2021 a lady by the name of Funeka was just plain rude, she got so angry that she did not want to assist us with anything , she kept on saying she does not help people who return parts, she also said we won't get any refund until I read the receipt and realized that they can hold a 20% holding fee , the security guard was also rude and he looked at me with a disgusted face, I think the security guard and Funeka are friends but they know nothing about customer service , they need to be taken to a customer service course because they will chase away customers with their rudeness, please may someone intervene because I'm never buying from ACE s****yard springs anymore because of them, they are just rude people.