If you were in customization mode, and moved a wall or something, the Item should be in your storage crate.
Just double click your house sign and cycle through the menu. It will say "Relocate Moving Crate" just click it and your stuff will be inside the little gold boxes (nope, those boxes are not removable).
Just remember that where ever your stading is where the crate will appear. It can be a pain in the posterior if you have a heavy item in there and want it on the 3rd floor, when you call the crate on the first floor.
*note* the crate will disappear after a time or when empty, simply go through the menu to get it out again. (unless its empty)
hope this helps!