The worst customer service experience

My sister and I went to buy 2 bottles of water at Picknpay in Strand street, Cape Town on Sunday only to be lambasted with humiliation and emotional *********. We made the purchase using R50 at the till. However the cashier named Koelthum gave us insufficient change, and insisted that we gave her R20 when we raised the matter. She then called her supervisor, who goes by the name of Kedibone. Who by the way didn't even ask what the matter was (her attitude stinks by the way). She got to the till and proceeded to count the money that was in the till. After she told us, we're lying, we gave the cashier R20. We disputed the matter and my sister advised we check the footage. They proceeded in doing so and 30 mins later Kedibone came to back to the cashier and confirmed that we gave her R50. No apology was given to us. We were just left standing there dumbfounded by the humiliation we were subjected to by the staff. On top of that there was not appropriate communication about the matter and Sandile who was the manager in sight on the day gave us attitude. He told us it's not their problem but cashier's and therefore they have nothing to apologize for. As for the cashier she just laughed and said "my bad". We feel humiliated as customers and were treated unfairly, especially from a superior representative of Picknpay. Being accused of lying and after being treated like shiy offending. I've decided never to shop at Picknpay Strand street again. I'll settle for the one in Gardens instead. The worst customer service experience ever.