Legal analysis: illegal. First of all, after you find that you have been cheated, you can negotiate with the merchant to return the goods, because the merchant cheated the consumer's right to know and your property suffered losses. Keep the invoice, it is the proof of your shopping.

Secondly, if negotiation fails, you can call the hotline 123 15 to defend your rights, and the complaint telephone number 123 15 can help you mediate the dispute. If economic violations are found, they will also be investigated and dealt with according to law 123 15.

Finally, the behavior of merchants may involve criminal offences, that is, fraud, which can be handled by the police.

Legal basis: Article 266 of the Criminal Law defrauds public or private property, and if the amount is relatively large, he shall be sentenced to fixed-term imprisonment of not more than three years, criminal detention or public surveillance, and shall also or only be fined; If the amount is huge or there are other serious circumstances, he shall be sentenced to fixed-term imprisonment of not less than three years but not more than ten years and shall also be fined; If the amount is especially huge or there are other especially serious circumstances, he shall be sentenced to fixed-term imprisonment of not less than 10 years or life imprisonment, and shall also be fined or confiscated. Where there are other provisions in this Law, such provisions shall prevail.