Bad customer service

On the 06/09/2020 I asked my daughter to buy formula at pick n pay Bopelong in Ivory park,she came back with the wrong one I then asked her go back for an exchange cause is not far from where we staying.she was supposed to buy Nan pelrgon no one she brought two.she came back and tell me they refused,I then call the store I was told that due to covid they can't do exchange,I asked for the I was told that he/she went to the meeting the will come back to me as soon as they finished,but they didn't.Monday morning I call the store again and ask for the who was not there again,the lady who said she is supervisor said she can help I told her my story and this one tells me that people are taking advantage of their store they go buy at the Pakistan stores and they come and exchange at their store.I don't understand how is that possible because they have their own barcode.im sitting with the wrong formula I can't give it to the baby she is only one month.so can u please help me to get the one I need