Issue:
If you notice that you have fewer contacts than you were expecting, it may be because your visibility settings are configured to display only your owned contacts.
Fixed: Checking your User Visibility Settings
You need to ask your admin assistance to check on your visibility settings.
Check the user's Visibility Settings.
Visibility settings have options to limit the user's access to see contacts. To change the settings, follow these steps:
Search for the user's name under the User tab.
Click Settings, then click Visibility Tab.
Set Contact's Visibility and Communications Visibility field to Everything instead of Owned Only.
Line Visibility Limit should also disable the Limit user's line visibility.
Read this guide to learn more about Visibility Settings.