Idiot Parent!

Why should I ask the pupils to stay back after school? The parents thought I am too free to give them extra class, and complaining that I am making trouble! Some of the pupils just say dont know, i dont know when i ask them if they can make it. Such irresponsible pupils and parents. Why should I do that? its for me or for the student? I done all this is for the student, they really thought I have nothing to do and I am free to trouble them! Idiot!