Appalling complaints handling by Flippin Nice management

I am appalled at the level of service my sister got from Flippin Nice staff together with management when she complained about substandard cakes she bought about 2 weeks ago. My sister is a family person and she always buys cake for us when it is someone's birthday. We are 10 in the house together with the little ones, and whenever she buys, she buys atleast 2 cakes at a time. We used to love and enjoy the cakes, until now recently when she bought, the 1 carrot cake was dry, the slices crumbled when cutting and it tasted funny. The other caramel chocolate cake bought also tasted like a cake that was standing for a long time and not freshly baked. My sister called the store and spoke to management who advised her to bring the cakes back and they'd assist. Upon returning the cakes, they were inspected and tasted by all staff and management and they agreed with one another that there was nothing wrong with the cakes. Mysister became infuriated that she was not seeing nor tasting funny things out of the blue. These are cakes she buys on the regular and they are always 'delic' hence her continuing to go back. My sister shares management made her feel belittled, disregarded and not valued as a customer. She wondered if the colour of her skin had anything to do with her being refused assistance, as as mentioned she is a loyal customer who buys regularly, never asks for discount, never has complained before, although now all of a sudden she is made to seem like she is 'coocoo'. When she shared this experience with me, it did not sit well at all. We all work hard for our monies and we expect value in all we buy and this time around there was no value nevermind customer centricity. I humbly ask my sister be contacted and the matter be rectified asap. I felt it uneccessary to throw my toys out of the cot as I believe such an experience can be handled neatly (nevermind the bitter taste it left in my sister's mouth at the time of returning the cakes). Her details are Ms Edna Pretorius ***.