Unacceptable service

During the riots last week I asked my cousin who is an essential worker to please purchase my baby formula while she was in the store, I had told her what formula it and told her what number to purchase so she purchased the brand and the No but unfortunately it was the lactose free version. With the riots ongoing and the stores being open for a short time frame I only managed to go today to exchange it. When I got to the store I was told to go to the cigarette counter the initial lady was very rude but she called another lady and she attempted to help however she needed the managers consent to change the formula considering that the formula was purchased during the riots. The manager just said no it cannot be exchanged and unfortunately the staff cannot go against him. The formula purchased was R220 and now that they don’t want to exchange it I am stuck with something that costs so much and out of pocket. This is unacceptable considering I have the receipt and the formula is sealed and in good condition. The formula was purchased at Pick n pay chatsworth and I attempted to exchange it at the same store.