You have no idea what they do or don't understand because all you have to go on is a noisy model of their mind in yours. You need to focus on facts, actions an

You have no idea what they do or don't understand because all you have to go on is a noisy model of their mind in yours. You need to focus on facts, actions and consequences. They don't understand how it works (your explanation) THEREFORE they question things that you thought had been put to rest? Ask them what would their opinion be IF (factual thing they're mistaken on) was true. Sometimes people do not disagree with you on facts; but their emotions can't let them agree on courses of action. Often you can direct people (with questions) towards verbalizing exactly what you wanted to tell them in the first place. They don't understand how it works (your explanation) THEREFORE they are saying falsehoods about it to others? Correct the facts one by one as they come by, their model will self-update eventually. That comes standard with the human being firmware. They don't understand how it works (your explanation) THEREFORE they are making assumptions or having expectations of your own work that are wrong? Kindly redirect by asking what factually they think is wrong with this part of your work, and what they think can be done about it, and who they think is the right person to do it. (I am being vague because you don't specify if the person is your superior, but if not, you can be more forceful in wording) There is a chance you are in fact misinterpreting their words, because of incompatible jargon, either of you sucking at communication, or irreconcilable difference of interests.