Parmalat growth milk 3+, from Checkers hyper gateway

Hi I purchased growth milk 3+ as I wanted to try it for my toddler, hence this was my first time buying it I purchased at Checkers gateway, got home and gave my child a glass, only to see that it's off, it was sour, I was so disappointed because I am giving this to my toddler, which could of caused her to get sick if I didn't taste it, the BB date on the box says 12/11/20 but still, it was off, I tried contacting checkers, to ask them to remove boxes that seemed bulky, but I did not get through. Therefore I hope my complaint is taken into account. Thank you