How to complain when the trash can is placed at the door?

Legal analysis: you can go to the property or the owners' meeting to complain.

Legal basis: Regulations on Property Management

Eighth property management area of all owners of the owners' meeting. The owners' congress represents and safeguards the legitimate rights and interests of all owners in the property management activities within the property management area.

Twentieth owners' congress and owners' committee shall cooperate with public security organs and residents' committees to do a good job in maintaining social order in the property management area. In the property management area, the owners' congress and the owners' committee shall actively cooperate with the relevant residents' committees to perform their autonomous management duties according to law, support the residents' committees to carry out their work, and accept their guidance and supervision. The decisions made by the owners' assembly and the owners' committee of residential quarters shall inform the relevant residents' committees and listen carefully to the suggestions of the residents' committees.