I'm not saying they lied to you... just that they are mistaken about it being installed. Probably they thought they installed it, but for whatever reason it's not installed properly.
You could try a stand-alone PHP file with any of these functions...
http://www.php.net/manual/en/ref.geoip.php
If the server tells you that the function isn't available, well... it's not available/installed.
The simplest one would probably just the be the call to get info about the geotargetting database:
PHP Code:
<?php
echo geoip_database_info();
If that PHP file throws an error, ask your hosting provider why that would be if it's installed.