EXTREMELY RUDE CASHIER

on the 26th march i went to FRESH STOP by the Caltex garage in the Woodstock area to buy some airtime i gave the cashier a R20 and asked for R10 MTN she handed me the piece of paper and as usual i just punched in airtime still in the shop i did not check the paper because i assumed its a R10 airtime. shortly after i punched in the airtime the cashier call me saying she gave me the wrong paper i went to her and in that same moment i received an sms saying i have recharged with a R180 airtime the lady totally flipped on me said im a ***** i knew what i was doing and was shouting at me the entire time i then spoke in a louder tone of voice and asked to see the manager she screamed i don't care about a manager the shop was full of people and the more i kept telling her i did not know the more she made a scene i then apologized and she did not want to hear she chased me out the shop very rudely i have never been this humiliated in my life before.the more i tried to tell her if i knew about the R180 airtime i would've left the shop immediately if i was a ***** but any good human would return it same time if i saw it was wrong.i do not appreciate the type of service this place has at nigh