I had a worn red rug glue itself to a rug I got in Cool Ranch and now I can't pick up or move either of them. Odd things happen with furniture sometimes. It it continues to be a problem, report it and K I can work on fixing it. Sometimes the glitches with furniture can turn out to be a plus letting you float items and build structures you can walk on. It seems there might be an issue with rugs. Gunn's Treasure crashing the game is not right . Check out how to contact Support under the "help" question mark. Details about which item was used, where, and how help them to fix it faster.
I too would like to be able to hang things in the stairwells and place things in the halls. I could hope they might allow that. I really don't see them letting us knock down walls or pillars though. I think the best you can do is find furniture that lets you hide the pillars you don't like, maybe a statue or a tree.