As someone who was a student in your class, I can speak for myself and say that I did give you a low rating
What the HECK is that sort of system for? Students rating teachers and those ratings have an effect on the teacher's annual review?
I hope I'm wrong but if that's how it works in that particular school there's no chance for professional integrity if the teacher has to keep the students happy. A teacher should always be in a position where he has an unchallengeable authority over students (with regard to the class, of course), and thus being able to be harsh when necessary without having to self-correlate his behaviour in fear of being financially punished. Otherwise it'll be screaming for A's for everyone.