I don't know. It's a bit extreme but maybe try putting her in the one she likes with the new one over the top? Only in the house, you would look a bit weird out and about like that! I don't think you should sell it, it took Freya about a month to get used to our new one and even now she doesn't love it, I have to keep her entertained whilst in it and not stop walking! I think she would prob get used to it in time.