Previewing a view does not show a phone number but when I look at the view by visiting the URL of the page it does?
They most likely modified a tpl.php file.  In the Views module when you are viewing to edit it, look for Theme: information and click information.

You will then see a list of possible tpl.php files.  If you see one that is not in the first position and bold, then you know they did some type of override on the tpl.php.  Look in the theme folder for that file name.

If its not in there, then you will want to look at your themes template.php for some type of override.  Finally, some people will put these overrides in a utility module.