S.B.
Dear Laura,
Since she drinks water and juice from a cup, I think it's a matter of her associating milk with her bottle and it's the bottle she doesn't want to give up.
Sometimes it takes a couple of days when you are breaking them from the bottle, but if you give in and give the bottle to her, it just sets you back at square one.
She'll drink milk from a cup when she gets it figured out there will be no more bottles. Teach her to drink from a straw. That might be a new novelty for her and maybe she'll drink her milk that way. Just keep trying.