Mon Cheri Wedding Dress 25277 Size 12

I bought this brand new Mon Cheri dress at Filene`s Basement because it was a great price ($260) at their annual sale-it`s beautiful. Retails 850-1200.
Problem is I wear a size 4 and alterations are telling me it is probably not going to work for me. I am sad and just want to get what I paid for it. The color is Ivory with ivory beading. I can send pictures. Thanks