Your dress may be safe. howerver, the more time that gopes by the less likely you are to find another that you love. I used to work for jessica mcclintock, so while you are looking for the owners, here are some questions and tips i have for you.....
Who is the manufacturor? do they have any retail shops? I replaced a dress for a woman overnight whose dressed burned up in a drycleaners fire. They also might be able to trace your order if the retailer is unavailiable, then at least you know if its comming.
how much time do you have left? do you need something right away? Go find a bridal outlet. you can get a dress off the rack and very cheap, so if your dress does turn up, you havent invested alot in a second.
Contact your disney consultant. mickey might be able to pull off some disney magic for you.