Dis-Chem exchanges

I bought baby formula, but unfortunatly my baby cannot drink formula anymore, the formula is still closed, but now 2 Dis-Chems in Rustenburg gives me 2 different stories as to why they cannot exchange it. The one says it is baby food and the other one says it must be exchanged within g 24hours, but the slip says all exchanges can be done withing 10 days 😠