PHP：现有数据输入

Can someone help me with my code. I'm confused on what happened on my code. It's just a INSERT data in PHP but when the data input there's an existing data that is empty even though it's not data coming from my form.

Here's my php code

<?php

$rfp_id  = $_POST['rfpid'];
$rfp_company_nbu = $_POST['company_nbu'];
$rfp_company_department = $_POST['company_department'];
$rfp_company_branch = $_POST['company_branch'];
$rfp_payee_id_num = $_POST['rfp_payee_id_num'];
$rfp_payee_name = $_POST['rfp_payee_name'];
$rfp_date = $_POST['rfp_date'];
$rfp_particulars = $_POST['rfp_particulars'];
$rfp_total_amount = floatval(preg_replace("/[^-0-9\.]/","",$_POST['rfp_total_amount']));
$rfp_words_amount = $_POST['rfp_words_amount'];
$rfp_remarks = $_POST['remarks'];

include("../dbconnection_set.inc.php");
include("../dbconnection_create.inc.php");

$qry = "INSERT INTO `tbl_rfp`(`rfpid`, `company_id`, `dep_id`, `branch_id`, `payee_name`, `payee_idnum`, 
        `current_date`, `rfp_particulars`, `rfp_total_amount`, `rfp_amount_words`, `rfp_details`, `rfp_status_id`)
        VALUES ('".$rfp_id."', (SELECT id FROM `tbl_nbu` WHERE nbu_desc = '".$rfp_company_nbu."'),
        (SELECT id FROM `tbl_department` WHERE dep_name = '".$rfp_company_department."'),
        (SELECT id FROM `tbl_branch` WHERE branch_name = '".$rfp_company_branch."'),
        '".$rfp_payee_name."', '".$rfp_payee_id_num."', '".$rfp_date."', '".$rfp_particulars."',
        '".$rfp_total_amount."', '".$rfp_words_amount."', '".$rfp_remarks."',
        (SELECT status_id FROM tbl_status WHERE status_id = '1'))";

        # (SELECT * FROM `tbl_userlist` WHERE fname LIKE '%$rfp_payee_name%' OR mname LIKE '%$rfp_payee_name%' OR lname LIKE '%$rfp_payee_name%')

if($conn->query($qry) === TRUE){
    echo "RFP Record created successfully";
    header('refresh: 3; url=rfp_encode_process.php');
}
else{
    echo "Error: " . $qry . "<br>" . $conn->error;
}

$conn->close();?>

Here's the sample data

Having the page refresh will make it run the same insert code thus explaining the duplicate?