I remember the film from the lates 80's / early 90's. It a US children's animated christmas film. Where a mother and her two children go to a dept store and she loses her toy rabbit... Any ideas??

It sounds like the Christmas show based on the comic strip For Better Or Worse: The Bestest Present Ever. For Better or for Worse: The Bestest Present (TV 1985) - IMDb (http://www.imdb.com/title/tt1051225/)