Do you mean that Linden Lab sent you a Landmark address to your home, but when you got there, it was a piece of land with no house built on it?
If that's what happened, it was an automated error.
To fix it, you stand on your land, click the land, and select "ABANDON LAND".
After you have abandoned that piece of land, wait a few minutes, then go back to the Second Life website, and apply again for a home. It will let you go through all the steps over again, and send you a 2nd landmark, and that one should have a house on it.