Cashier behavior

On the 21st of November 2021, I went to Woolworths Festival mall to buy my favorite red velvet cake as usual. I also bought few items along with the cake. At the till the total amount was R258.77, I gave the cashier 2 R200 she said to me yohh I therefore took 1 R200 back and look for R100 in my bag thinking that she doesn't have change. When the cashier opened the till she had enough money for change, I asked the cashier why was she saying yohh because she do have change. The cashier said yes I do have change, I politely asked the cashier for R200 change after paying. The cashier said to me, what if that your R200 is **** money. I didn't respond, she continued by saying this R200 might be **** then she gave me the change. I have never been offended like that in my life. I left the Woolworths store heartbroken and angry. The cashier name was Y Vikilahle as per the slip.