$cloud_url = "http(s)://client.sendsms.com/api/sendsms.aspx?";
$gsm = $country_code . $contact;

$clould_pass=MD5($cloud_pass);
$msg = urlencode(stripcslashes($message));
$post_vars = "username=".$cloud_user."&pass=".$cloud_pass."&sender=".$sender."&smstext=".$msg."&isflash=0&gsm=".$gsm;

$ch = curl_init($cloud_url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS,$post_vars);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$response = curl_exec($ch);

$err = curl_error($ch);
curl_close($ch);
if ($err) {
 echo "cURL Error #:" . $err;
} else {
 echo $response;
}