If you bought a fake watch on Xianyu and found out about it half a month later, it may be useful to call the police.

According to the "Criminal Law of the People's Republic of China", anyone who knowingly sells goods that are counterfeit registered trademarks and obtains a relatively large amount of illegal income or has other serious circumstances shall be sentenced to fixed-term imprisonment of not more than three years and shall also be fined. Or a fine alone; if the amount of illegal gains is huge or there are other particularly 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.

Therefore, if you believe that your rights and interests have been violated, you can report the case to the public security agency and provide relevant evidence and information. However, whether calling the police can solve the problem still needs to be judged based on the specific situation.