You don't have any trusted negative feedback. Just two neutral ones so it doesn't really matter but you'll have to either live with it or try persuade those who left you it to remove them (which they probably wont).
Try saying it to the moderators. Probably they can make something.
Staff don't remove or moderate feedback.
Are you sure? I have seen a lot of people have been removed from the default trust list due their (left) negative trusts and you are saying that the trust system is not moderated (I think it is no-sense) but I accept your opinion.