Stinking attitude

This morning I went for shopping at Pick n Pay Oakfields (Benoni). I was assisted by cashier who goes by the name of Martha Mamabolo, throughout the transaction she continuously called me 'Mam' which I didn't prefer so asked her not to and she said well I should get her arrested and I couldn't believe that she said that and I said No. And she then said well that's how we were trained and I said but I don't want to called that and she didn't stop,gave me my receipt with an attitude and said 'Thank you MAM'. Now as I was at the shop i found this old man who happens to work there and I asked for the manager and he said I should talk. I gave him the whole story and eventually when I was done he said he would tell the manager :-! But gave me some nonsensical story about them referring to everyone like that and I said I don't dispute that but I was specific with that girl that I refuse to be addressed as such.