SOAP Call in PHP with Class version

[Mathaalbhai]

class getSoap{
    public $soapResults;
    public function callSoap($call){
        $this->call = "soapID";
        $client = new SoapClient("http://example.com?wsdl");
        if($client){
        $soapResults= $client->getSiteInfoByManagerId($calloutZone);
        return $soapResults->opsID;
    }  else {
        echo 'Error encountered while attempting to get netOpsCom info';
    }
}}
$ID = isset($_GET['ID']) ? $_GET['ID'] : 0;
$calloubaba = new getSoap($ID);
var_dump($calloubaba);

When I dumb class I get null Value. I would greatly appreciated.

[droopsnoot]

I may be showing my ignorance, but what causes the callSoap() function to execute? I have no object experience (yet), so that might be relevant.