I didn't realize what I was putting into my body, so I think I should refuse to pay for this cocktail
Are you serious? Did you not drink the cocktail?
Of course, but cocktails cause cancer and infertility and also bad breath, so I feel it's unfair to charge me for it.
It is okay to not want to pay for something you didn't drink, but you already drank it. You didn't have to let people push you to drink especially if you didn't want to drink that or any other alcoholic drinks.
Come on man... Those drinks are cancerous.
I think you're right in wanting to avoid cancerous products. However, you already drank it so you need to pay. In the future check into something before consuming it.