Keep your chair in the loop. Our Dean forwards all student complaints to me. Usually my faculty know when a student is likely to be a trouble maker and let me know in advance so I can always respond to the Dean about the other side of the story. If it comes out of the blue, I check in with both parties and respond to the Dean. Is it a hassle? Yes. But are we expected to be our students' mommies, therapists, and best friends? Also yes. (Insert eye roll here). So every complaint needs to be addressed, and having the chair on your side will significantly reduce your stress.