The restaurant is not allowed to take away the free drink, how can I defend my rights

Article 4 of the General Principles of the Civil Law stipulates that "civil activities shall follow the principles of voluntariness, fairness, equivalent compensation, and good faith". Article 4 of the Contract Law stipulates that "the parties shall enjoy the right to voluntarily conclude a contract in accordance with the law"; Article 3 stipulates that "the parties to a contract are equal in legal status and one party may not impose its will on the other". Article 9 of the Law on the Protection of Consumer Rights and Interests stipulates that "consumers have the right to choose goods or services independently"; Article 24 stipulates that "business operators shall not make unfair or unreasonable provisions to consumers by means of standard contracts, notices, statements, store notices, etc., or reduce or exempt them from civil liability for harming the legitimate rights and interests of consumers".

Article 12 of the Anti-Unfair Competition Law stipulates that "when a business operator sells goods, it shall not tie in the sale of goods against the will of the purchaser or attach other unreasonable conditions".

You, before you entered the restaurant, everyone had a sign written on it, but you didn't see it clearly! You go first, people's announcements are at the door, on the door, how do you want to defend your rights! Don't go next time.