After getting a part of the amulet from the witch, I've used it in the barn, and the other gal came and I've ordered her to kneel, then I've used it for the 2nd time and she came unaffected, the quest says "go talk with the witch" but I'm not able to interact with the witch, and won't let me use the amulet in the barn, when I click "use", nothing happens and the inventory window just closes down.