Fed Ex Delivers to Wrong Address?

I had order my wedding rings from a Jewelry store in LA. As promised, they sent them via fed ex. Fed ex delivered them to the wrong address and the person there signed for them. I informed fed ex of their error and they said that they would have the courier to go back and get the package. My question is; what happens if the person that signed for the package will not give it back to the courier? I am very upset about this because I spent a lot of money on our wedding rings.