Terrible Service

On the 25th of September I purchased a caton of Ultra Mel Zero from Maponya only to find out when I got home the item had already been opened and consumed, I phoned in and spoke to Humphrey who said I could come in anytime and speak to the manager on duty, when I got the I explained my dilemma to the cashier and asked to speak to the manager when she got back I was told the manager (Sphiwe) couldn't be bothered and was given a new caton of which I refused, no apology was given and no I am sure if I was a white person Sphiwe would have come at the speed of lightning with coffee and biscuits. I don't know the reason why it was opened and if the contents had been contamined and I hate to imagine if my kid had consumed it. I am appalled at the treatment I received and contemplating closing my store card and credit card which I pay religiously on time. I demand an apology from Sphiwe and woolworths and want to know what would be done about this.