I watched this animation on VHS, 10 to 14 years ago.
It was about a girl (might have been about a boy as well) who ventured to a bewitched house. I remember the house to be black, castle-like, or Gothic, and it could have been
smaller on the outside bigger on the inside. An evil witch lived there.
Long story short, the girl runs from the house, only to find out that some time - 2 years, not sure about that - has passed, and no one remembers her. She might have had a brother who aged significantly, or doesn't remember her as well.
She goes back to the witch's house and starts serving her. Also, the witch might have gotten younger.
I don't remember the ending, or anything else related to the plot.
It was dubbed in Russian, and the original language was most probably English, though I don't exclude the possibility that this was in Japanese.