Unfair customer treatment

I am so ashamed & disgusted by how shoprite Bethlehem has dealt with a conflict with one of it's customers today. My mother in-law went to buy groceries, she had groceries packed on the upper & lower part of the trolley. When she got to the counter she paid for the food but she had forgotten about the groceries on the lower part of the trolley. On her way out she was confronted by the security guy and she explained to him that she completely forgot about them. She was willing to pay for those groceries but the security guy handcuffed her instead and paraded her and also saying out loud to everyone that she was a ***** who had ****** groceries. She was taken to the manager and she insisted that they call the police of which they did call the police but the police didn't come. The manager said to my mother in law that she must clean the toilets and the canteen as a punishment. Now this is a 50 years old woman who had forgotten about paying some of the groceries and was willing to pay for them yet the security and the management of shoprite took her for a ***** and did not take into consideration that she's might have indeed forgotten about the other groceries and that she was willing to pay for the rest of the groceries. She had paid groceries for R260.34 and was taken for a ***** for forgetting to pay for groceries worth R67. 71. What makes matters even worse was that she was asked to clean the toilets and the canteen. She was not even given a mask nor gloves.