PHP SMS Mail Script Error?

[Joe34]

Alright here is my code...

<?php

                $Connect = mysql_connect("","","");
        $DB = mysql_select_db("");
                    
        if(!$Connect || !$DB)
        {
            die("MySQL Error #1! Try Again Later!");
        }


        if($_POST['car'] == "Alltel")
        {
            $To = $_POST['num']."@message.alltel.com";
        }
        if($_POST['car'] == "AT&T")
        {
            $To = $_POST['num']."@txt.att.net";
        }
        if($_POST['car'] == "BoostMobile")
        {
            $To = $_POST['num']."@myboostmobile.com";
        }
        if($_POST['car'] == "CentennialWireless")
        {
            $To = $_POST['num']."@myblue.com";
        }
        if($_POST['car'] == "EinsteinPCS")
        { 
            $To = $_POST['num']."@einsteinmms.com";
        }
        if($_POST['car'] == "Nextel")
        {   
            $To = $_POST['num']."@messaging.nextel.com";
        }
        if($_POST['car'] == "Sprint")
        { 
            $To = $_POST['num']."@messaging.sprintpcs.com";
        }
        if($_POST['car'] == "T-Mobile")
        { 
            $To = $_POST['num']."@tmomail.net";
        }
        if($_POST['car'] == "USCellular")
        { 
            $To = $_POST['num']."@mms.uscc.net";
        }
        if($_POST['car'] == "VerizonWireless")
        {
            $To = $_POST['num']."@vtext.com";
        }
        if($_POST['car'] == "VirginMobile")
        {
            $To = $_POST['num']."@vmobl.com";
        }
        if(isset($To))
        {
        if(!mail("$To","Thanks","Hi Mom!","From: Joe Burnett"))
        {
            die("Error!");
        }
        }
        $Query = mysql_query("INSERT INTO subscribers (formsource,user,car,num)
                            VALUES ('OTHER','JoeB','$Car','$Num')");
                   if(!$Query)
                   {
                       die("Error");
                   }
        
        header("LOCATION: http://www.google.com/");

        ?>

In the code I know Verizon Wireless works, but Sprint doesn't work? Do I have the wrong email or what is the problem? Also if someone has another carrier other than Verizon or Sprint then please contact me and I want you to try this and tell me if you will recieve a text message.