Tyre plugs

Parked my car at engen Doornfontein near Maboneng, came back to flat front and back tyres. One of the employees remove tyre plugs, actually stole them. Then they show where to get them, to my surprise the very same employee tells the guy assisting me that he'll give him more customers and he says that in Venda thinking I dont understand the language. Is this how your employees hustle people? How many people have they done this to? I'm really disappointed