Horrible experience from Shoprite

i bought 4 boxes of S26 baby milk from shoprite in athlone for my son and sisters daughters , on Monday i was in such a rush that i did not check the if i took all 4 of the same as the school called me that my son got very sick and i rushed to get home to fetch him , i was suppose to take 4 x 0-6 months , but instead i took 2 x 0-6 and 2 x 1-3 years , i only noticed when i got home , the next day i sent my daughter to Shoprite in gatesville to exchange it for the correct ones she got treated so badly by one of the supervisors stating that they not taking it back and their policy states that they not allowed to change baby products no where on their till slips nor has any of the staff in formed me that you not allowed to change it , she was so rude to my daughter that my daughter left , then she went to Shoprite Charlesville , she got treated exactly the same what then happened is the lady at the front counter opened these boxes to check , so when sent a complain through to their customer service stating what are we to do with these as our children are 3month and 2 months old , we would just like to exchange , we didnt want our money back , the lady that called back stated that the manager advised that they cannot help us , no offense to anyone but if i were to be a white person or black we would have been helped very quickly , they treating us like we are ********* , what kind of customer service is that.