It's a good idea to back up all your work. I tend to have made a habit of it because I work from two computers so I move it back and forth with my flash drive. Even if you don't have a flash drive just go to Documents > Electronic Arts > The Sims 3 Create A World Tool Folder and copy the UserToolData folder then paste it somewhere on your desktop or somewhere on your computer.
This folder is all you need to back up. It contains everything you have done, all your work, CAW textures etc and all your worlds.
*Especially* back up before a new patch! >_>
I'm sorry for you guys and I know how it is to lose a world. I hope they can reverse this and recover your data!
