PHP Fatal error: Uncaught TypeError

Por algum motivo meus getters estão retornando NULL (todos eles) como corrijo? Erro que recebo: PHP Fatal error: Uncaught TypeError: Account::returnName(): Return value must be of type string, null returned in /workspace/Main.php:38

<?php 

class Account
{
    private $holderDocument;
    private $holderName;
    private $accountBalance;
    private $accountLimit;
    private static $Accounts = 0;

    public function __construct(string $holderDocument, string $holderName)
    {
        $this->holderDocument = $holderDocument;
        $this->holderName = $holderName;
        $this->checkName($holderName);
        $this->accountBalance = 0;
        $this->accountLimit = 0;
        self::$Accounts++;
    }

    public function returnAccounts()
    {
        return $this->Accounts;
    }

    public function returnBalance(): float
    {
        return $this->accountBalance;
    }

    public function returnDocument(): string
    {
        return $this->holderDocument;
    }

    public function returnName(): string
    {
        return $this->holdeName;
    }

    public function withdrawal($amountWithdraw): void
    {
        if (($this->accountBalance+$this->accountLimit) < $amountWithdraw)
        {
            echo "You have insufficient funds in your account to complete the transaction";
        return;
        }
    $this->accountBalance -= $amountWithdraw;
    echo "Withdrawal successfully completed", PHP_EOL;
    }

    public function deposit($amountDeposit): void
    { 
        if ($amountDeposit < 0)
        {
            echo "It's not possible to make a deposit of a negative amount.";
        return;
        }
    $this->accountBalance += $amountDeposit;
    echo "Deposit successfully completed", PHP_EOL;
    }

    public function wireTransfer(float $amountTransfer , Account $targetAccount)
    {
        if (($this->accountBalance+$this->accountLimit) < $amountTransfer)
        {
            echo "You have insufficient funds in your account to complete the transaction";
        return;
        }
    $this->withdrawal($amountTransfer);
    $targetAccount->deposit($amountTransfer);
    }

    public function checkName(string $holderName)
    {
        if (strlen($holderName) < 3)
        {
            echo "The name must have a 3 characters lenght";
            exit();
        }
    }
}
$firstAccount = new Account("123459831", "João Pedro");
$firstAccount->deposit(500);
$firstAccount->withdrawal(200);
$firstAccount->returnName();


?>