Which department should the security guard complain to?

This kind of situation can be complained to the property.

Complain directly to the property company, either in person or by letter or phone. You can also complain directly to the security management unit, usually the security company. Complaints should have specific events, the content of complaints should be clear, relevant evidence should be kept, and some security performance requirements should be understood before complaints.

The specific complaint department may vary from company to company, so you can consult the management or human resources department of the security company or organization first to understand the specific complaint process and department.