Disrespected by their worker

Today as I was in a deli area at Shoprite Secunda plaza ( Shoprite close to Absa) I was disrespected and insulted by a female and male worker that said and laughed at me for " istaff sikaJoseph" the guy Joseph was working. Please Shoprite managers teach your employees manners, being small does not give them authority to talk as they wish. If they didn't had anything to say why don't they shut their mouths. I'm not happy about their behavior.