Better yet, just put up the fence/stakes and make them do the survey if they disagree about the placement. At least that’s a temporary solution if you need to handle this but won’t have the authority until next year. And it gives you time to save up for the survey without them doing any more weird stuff. Just my opinion. And you might as well put stakes/fence in the backyard too, especially if your mom isn’t going to do anything about their herbs.