How to deal with teacher

My child is the kindest ever and not just in my eyes but everyone bar his teacher.

Today I was told he is aggressive because he stared at his teacher and that he runs around.

If the teacher writes report that he's aggressive how do I prove she is wrong. When I approached another teacher, the teacher said he was good. I don't want him diagnosed wrongly with the report of a teacher.

It's not that I don't want to believe it, but I know my child and no other professional reports this.

I just don't know what to do and can't understand why teachers are listened to over parents

Any help please