Ошибка: вызов функции-члена getPendingTransaction () для null [Symfony2]

Я занимаюсь разработкой сайта электронной коммерции. Я хочу разрешить пользователям осуществлять платеж через Paypal. Поэтому я установил и настроил следующий пакет:

"jms/security-extra-bundle": "dev-master",
"jms/payment-core-bundle": "master-dev",
"jms/di-extra-bundle": "1.7.0",
"jms/payment-paypal-bundle": "dev-master"

У меня появляется следующая ошибка, когда я нажимаю на кнопку Оплатить:

Ошибка: вызов функции-члена getPendingTransaction () для null

$instruction = $commande->getPaymentInstruction();
if (null === $pendingTransaction = $instruction->getPendingTransaction()) {
$payment = $this->ppc->createPayment($instruction->getId(), $instruction->getAmount() - $instruction->getDepositedAmount());
} else {
$payment = $pendingTransaction->getPayment();

Это мои контроллеры:

    /**
* @Route("/complete/{id}", name = "payment_complete")
*/
public function completeAction(Commandes $commande) // id of the order
{

$instruction = $commande->getPaymentInstruction();
if (null === $pendingTransaction = $instruction->getPendingTransaction()) {
$payment = $this->ppc->createPayment($instruction->getId(), $instruction->getAmount() - $instruction->getDepositedAmount());
} else {
$payment = $pendingTransaction->getPayment();
}

$result = $this->ppc->approveAndDeposit($payment->getId(), $payment->getTargetAmount());
if (Result::STATUS_PENDING === $result->getStatus()) {
$ex = $result->getPluginException();

if ($ex instanceof ActionRequiredException) {
$action = $ex->getAction();

if ($action instanceof VisitUrl) {
return new RedirectResponse($action->getUrl());
}

throw $ex;
}
} else if (Result::STATUS_SUCCESS !== $result->getStatus()) {
throw new \RuntimeException('Transaction was not successful: ' . $result->getReasonCode());
}
// if successfull, i render my order validation template
return $this->render('FLYBookingsBundle:Post:validation.html.twig', array('commande' => $commande));

}

/** @DI\LookupMethod("form.factory") */
protected function getFormFactory()
{
}

/**
* @Route("/cancel", name = "payment_cancel")
*/
public function CancelAction()
{
$this->get('session')->getFlashBag()->add('info', 'Transaction annulée.');
return $this->redirect($this->generateUrl('yourTemplate'));
}

}

Это моя сущность, командиры:

<?php

namespace FLY\BookingsBundle\Entity;
use Application\Sonata\UserBundle\Entity\User;
use Doctrine\ORM\Mapping as ORM;
use JMS\Payment\CoreBundle\Entity\PaymentInstruction;
/**
* Commandes
*
* @ORM\Table("commandes")
* @ORM\Entity(repositoryClass="FLY\BookingsBundle\Entity\CommandesRepository")
*/
class Commandes
{
/**
* @var integer
*
* @ORM\Column(name="id", type="integer")
* @ORM\Id
* @ORM\GeneratedValue(strategy="AUTO")
*/
private $id;

/**
* @ORM\ManyToOne(targetEntity="Application\Sonata\UserBundle\Entity\User", inversedBy="commandes")
* @ORM\JoinColumn(nullable=true)
*/
private $user;

/**
* @var boolean
*
* @ORM\Column(name="confirm", type="boolean")
*/
private $confirm;

/**
* @var \DateTime
*
* @ORM\Column(name="date", type="datetime")
*/
private $date;

/**
* @var integer
*
* @ORM\Column(name="reference", type="integer")
*/
private $reference;

/**
* @var array
*
* @ORM\Column(name="commande", type="array")
*/
private $commande;

/**  * @ORM\OneToOne(targetEntity="JMS\Payment\CoreBundle\Entity\PaymentInstruction")
*/
private $paymentInstruction;

public function getPaymentInstruction()
{
return $this->paymentInstruction;
}

public function setPaymentInstruction(PaymentInstruction $instruction)
{
$this->paymentInstruction = $instruction;
}

/**
* Get id
*
* @return integer
*/
public function getId()
{
return $this->id;
}

/**
* Set confirm
*
* @param boolean $confirm
* @return Commandes
*/
public function setConfirm($confirm)
{
$this->confirm = $confirm;

return $this;
}

/**
* Get confirm
*
* @return boolean
*/
public function getConfirm()
{
return $this->confirm;
}

/**
* Set date
*
* @param \DateTime $date
* @return Commandes
*/
public function setDate($date)
{
$this->date = $date;

return $this;
}

/**
* Get date
*
* @return \DateTime
*/
public function getDate()
{
return $this->date;
}

/**
* Set reference
*
* @param integer $reference
* @return Commandes
*/
public function setReference($reference)
{
$this->reference = $reference;

return $this;
}

/**
* Get reference
*
* @return integer
*/
public function getReference()
{
return $this->reference;
}

/**
* Set commande
*
* @param array $order
* @return Commandes
*/
public function setCommande($commande)
{
$this->commande = $commande;

return $this;
}

/**
* Get commande
*
* @return array
*/
public function getCommande()
{
return $this->commande;
}

/**
* Set user
*
* @param \Application\Sonata\UserBundle\Entity\User $user
* @return Commandes
*/
public function setUser(\Application\Sonata\UserBundle\Entity\User $user = null)
{
$this->user = $user;
return $this;

}

/**
* Get user
*
* @return \Application\Sonata\UserBundle\Entity\User
*/
public function getUser()
{
return $this->user;
}
}