I recently ordered a rug and proptly returned it. I did not have any problems but I was on them constantly, calling to inform it was sent, calling to check in, etc. I was very careful to re-package everything EXACTLY the way they specified and follow all directions to a 't'. On the front end, I also asked the person I placed the phone order with about their return policy and she did say sometimes they only do a partial refund but it is usually in extreme cases (shirt covered in cat hair for example)
My advice is to call first. If you are a first time customer, they will also probably cut you some serious slack. In general, I don't think it is a problem for people returning unused merchandise (or defective)
Hope that helps!