The waitress made me pay for an item she left off my bill and I don't want to give her a tip.
Do you think she meant to do this?
Yes, I do.
I can understand not wanting to give a tip if you feel the service person did not do a good job. It is a way of telling the person that they did something wrong.
You are right. Maybe I should also report her to her manager!
You can if you want, even though you are letting her know that her service was unacceptable already by not tipping. But if you want to prevent her to do it to anybody else you can let her manager know.