Not Happy Client

I am a loyal customer of Mochachos in Ghandi Square. Love the food. However I was very disappointed in the service. I went to buy regular fries, as they are my favorite. I used my card to swipe, & the lady there told me I cannot swipe anything less than R50! Since when? How is this possible, in the South Africa we live in. I dont carry cash, I believe it's not safe to do so. Absolute *******! Please rectify this, as u will lose customers for staff that don't clearly give a damn about customer service