Blank Return ~ Simple Register Page

Question

so I have been trying to successfully build a register form using PHP and SQL, but I am new and I suck. Here is the code, it outputs no error at all, in fact it just doesn't run at all.

<?php
if (isset($_POST['signup-submit'])){

require 'includes/dbh.inc.php';

$username = $_POST['uid'];
$password = $_POST['pwd'];

if (empty($username) || empty($password)){
  header("Location: ../register.php?error=emptyfields");
  exit();
} else {

  $sql = "SELECT uidUsers FROM Users WHERE uidUsers=?";
  $stmt = mysqli_stmt_init($conn);

  if (!mysqli_stmt_prepare($stmt, $sql)){

    header("Location: ../register.php?error=sqlerror");
    exit();

  } else {

    mysqli_stmt_bind_param($stmt, "s", $username);
    mysqli_stmt_execute($stmt);

    mysqli_stmt_store_result($stmt);
    $resultCheck = mysqli_stmt_rum_rows($stmt);

    if ($resultCheck > 0){
      header("Location: ../register.php?error=usernametaken");
      exit();

    } else {

      $sql = "INSERT INTO Users (uidUsers, pwdUsers) VALUES (?, ?)";

      $stmt = mysqli_stmt_init($conn);

      if (!mysqli_stmt_prepare($stmt, $sql)){
        header("Location: ../register.php?error=sqlerror");
        exit();
      } else {

        $hashedPwd = password_hash($password, PASSWORD_DEFAULT);

        mysqli_stmt_bind_param($stmt, "ss", $username, $hashedPwd);
        mysqli_stmt_execute($stmt);

        header("Location: ../register.php?signup=success");
        exit();
      }
    }

  }
}

mysqli_stmt_close($stmt);
mysqli_close($conn);
} else {
header("Location: ../register.php");
exit(); }?>

I am quite confused as to why it is returning a blank result,so please help me out. Thanks! :D