Health code violation?

So here’s the story; I went to 7–11 at lunch to get a Rockstar Roasted. Which is like a coffee flavoured energy drink and at the bottom of it, after I have drank the whole drink, there are soggy chunks that are like the chunks you get in sour milk. So one of my teachers goes to the 7–11 and she ends up getting my a new one which should be “good.” She also said if there was another problem that I should go complain again. Well I had science after lunch and I couldn’t drink in the lab so when I was walking home from school I discovered this one had chunks in it too. 7–11 is kind of far from my home and I’m going to be busy later, so I can’t really complain tonight. Would it be as effective to go complain tomorrow after school? I still have the can. Also, I don’t want another Rockstar because it seems they are all disgustingly defective. Would it be right to go and just ask for my money back? I am literally never buying anything from there again. I am completely disgusted.