```php
<?php

error_reporting(E_ALL);
ini_set('display_errors', 1);

session_start();

header('Content-Type: application/json');

include "general.php";
include "connect.php";

if(!isset($domain))
{
    $domain = "247sms.com";
}

/*
|--------------------------------------------------------------------------
| GOOGLE RECAPTCHA SECRET KEY
|--------------------------------------------------------------------------
*/
$secretKey = "6LcongEtAAAAALHYyjJZbZLxMUehcIar_Y8__MSl";


/*
|--------------------------------------------------------------------------
| CHECK RECAPTCHA
|--------------------------------------------------------------------------
*/
if(
    !isset($_POST['g-recaptcha-response']) ||
    empty($_POST['g-recaptcha-response'])
)
{
    echo json_encode([
        "status" => "error",
        "message" => "Please complete the reCAPTCHA"
    ]);
    exit();
}

$captcha = $_POST['g-recaptcha-response'];

$verifyURL =
    "https://www.google.com/recaptcha/api/siteverify".
    "?secret=".$secretKey.
    "&response=".$captcha;

$verifyResponse = file_get_contents($verifyURL);

if($verifyResponse === false)
{
    echo json_encode([
        "status" => "error",
        "message" => "Unable to connect to Google reCAPTCHA"
    ]);
    exit();
}

$responseData = json_decode($verifyResponse);

if(!$responseData || !$responseData->success)
{
    echo json_encode([
        "status" => "error",
        "message" => "reCAPTCHA verification failed"
    ]);
    exit();
}


/*
|--------------------------------------------------------------------------
| RANDOM CODE GENERATOR
|--------------------------------------------------------------------------
*/
function rand_string2($length)
{
    $chars = "0123456789";
    $str = "";

    for($i = 0; $i < $length; $i++)
    {
        $str .= $chars[rand(0, strlen($chars)-1)];
    }

    return $str;
}


/*
|--------------------------------------------------------------------------
| GET FORM VALUES
|--------------------------------------------------------------------------
*/
$username    = trim($_POST["username"]);
$pass        = trim($_POST["password"]);
$email       = trim($_POST["email"]);
$phonenumber = trim($_POST["phone"]);
$address     = trim($_POST["address"]);
$fullname    = trim($_POST["fullname"]);
$state       = trim($_POST["state"]);
$country     = trim($_POST["country"]);
$referrer    = trim($_POST["referrer"]);
$accounttype = trim($_POST["currency"]);


/*
|--------------------------------------------------------------------------
| VALIDATE REQUIRED FIELDS
|--------------------------------------------------------------------------
*/
if(
    $username == "" ||
    $pass == "" ||
    $email == ""
)
{
    echo json_encode([
        "status" => "error",
        "message" => "Please complete all required fields"
    ]);
    exit();
}


/*
|--------------------------------------------------------------------------
| GENERATE EMAIL CODE
|--------------------------------------------------------------------------
*/
$emailcode = rand_string2(6);


/*
|--------------------------------------------------------------------------
| SAVE TO SESSION
|--------------------------------------------------------------------------
*/
$_SESSION['username']    = $username;
$_SESSION['password']    = $pass;
$_SESSION['email']       = $email;
$_SESSION['phone']       = $phonenumber;
$_SESSION['address']     = $address;
$_SESSION['fullname']    = $fullname;
$_SESSION['state']       = $state;
$_SESSION['country']     = $country;
$_SESSION['referrer']    = $referrer;
$_SESSION['accounttype'] = $accounttype;
$_SESSION['emailcode']   = $emailcode;


/*
|--------------------------------------------------------------------------
| SAVE ENQUIRY
|--------------------------------------------------------------------------
*/
$query = "
INSERT INTO Enquiry
(
    username,
    phonenumber,
    email,
    emailcode,
    domain,
    dateused
)
VALUES
(
    '".$username."',
    '".$phonenumber."',
    '".$email."',
    '".$emailcode."',
    '".$domain."',
    NOW()
)
";

$result = mysqli_query($con, $query);

if(!$result)
{
    echo json_encode([
        "status" => "error",
        "message" => mysqli_error($con)
    ]);
    exit();
}


/*
|--------------------------------------------------------------------------
| SEND EMAIL
|--------------------------------------------------------------------------
*/
$subject = "Registration Verification Code";

$message = "
Dear ".$username.",

<br><br>

Your verification code is:

<br><br>

<b>".$emailcode."</b>

<br><br>

247sms.com
";

$headers  = "MIME-Version: 1.0" . "\r\n";
$headers .= "Content-type:text/html;charset=UTF-8" . "\r\n";
$headers .= "From: noreply@247sms.com" . "\r\n";

$mailSent = mail(
    $email,
    $subject,
    $message,
    $headers
);

if(!$mailSent)
{
    echo json_encode([
        "status" => "error",
        "message" => "Email could not be sent"
    ]);
    exit();
}


/*
|--------------------------------------------------------------------------
| RETURN HTML
|--------------------------------------------------------------------------
*/
$verificationHtml = '

<div id="verificationMessage"></div>

<form id="verifyForm">

<div class="row uniform">

<div class="8u 12u$(small)">

<p>EMAIL CODE</p>

<input
    type="text"
    name="emailcode"
    maxlength="10"
    placeholder="Email Code"
    required
/>

</div>

<div class="12u$">

<ul class="actions">

<li>

<input
    type="submit"
    class="special"
    id="verifyBtn"
    value="Submit"
/>

</li>

</ul>

</div>

</div>

</form>

';


/*
|--------------------------------------------------------------------------
| SUCCESS RESPONSE
|--------------------------------------------------------------------------
*/
echo json_encode([
    "status"  => "success",
    "message" => "Verification code sent to your email",
    "html"    => $verificationHtml
]);

?>
```