My question involves defamation in the state of: California

Two students made a number of false accusations against me to their school conselor so that they could switch to another class. Both had a record of discipline problems in the class and did not like me holding them accountable for their bad behavior. I have a number of statements from other students in that class that completely refute what the two claimed. Their false claims resulted in a negative letter being placed in my personnel file. The district basically accepted their stories without question.

Both are 18. I am going to send their parents a certified letter demanding that they, in writing, retract their false accusations or face a small claims suit for $5000.

What do you think?