Appearance, Online accounts disappeared in System Settings in Ubuntu 13.10

I was installing some apps and icons then I noticed that there were about 4 games installed, so I went to the Software Centre to remove them. Then I wanted to add my Facebook account to Online Accounts but Alas! It was disappeared. But it was there when I searched for Online Accounts in the Unity Dash.

Please help me. I think I might have uninstalled the wrong packages. Can anyone tell me the packages that are associated with them?

Below are screenshots of my settings window and the Online Accounts icon in the Unity Dash.

The solution for me was to install that specific package that was missing:

sudo apt-get install unity-control-center-signon gnome-control-center-unity

Try to reinstall gnome-control-center using the following command:

sudo apt-get install --reinstall gnome-control-center

I think I have added the gnome3 ppa in my ubuntu 13.10 for the sake of installing gnome desktop environment but after adding the ppa I changed my mind so I removed it. But before removing it I ran a update, so I think the gnome 3 ppa replaced the online acoounts, appearance, etc etc apps and so I installed synaptic. Go to the gnome-control-center and mark for complete removal and then applied the changes then I installed the gnome-control-center through synaptic and voila it worked. The problem was solved.

But this method a little bit dangerous. Can any expert have a eye on this.