Bad customer service

I'm at Westgate Mall trying to buy me and my family some ice cream and immediately my brother produce a 100 rands note before he can even open a mouth to place the order the sales chased him away saying she can't sell him ice cream coz there is no change. I was surprised because were going to buy icecream for more than 100 rand and she didn't want to know how many are we buying. I asked her you don't even know how many are we buying she said she answered rudely and says she doesn't care. My heart pained but I'm asking what kind of customer service is that