Your phone service provider (say, AT&T or Sprint) doesn't know the contacts you put in your phone. Just like they don't know what music and pictures you put on it. They only know what you send and receive, and there are limits to what they keep of that (for privacy reasons).
Is it possible, through your cell phone provider, to retrieve old contacts and text messages that were once on a SIM card? I had always thought that they might have a index of sorts, showing whom you've added as a contact and whom you've texted. Does that exist?