Symfony2 and FOSUserBundle: performing other operations when updating/creating a user - symfony

Question

I'm using FOSUserBundle on Symfony2.
I extended the User class to have additional fields, therefore I also added the new fields in the twigs.
One of those fields is a licence code. When a user fills in that field I want to perform a connection to DB to look if that license is valid. If not returns an error, if yes creates an event in the "licenceEvents" table assigning the current user to that license.
[EDIT] As suggested I created a custom validator (which works like a charm), and I'm now struggling with the persisting something on DB once the user is created or updated.
I created an event listener as follows:
<?php
// src/AppBundle/EventListener/UpdateOrCreateProfileSuccessListener.php
namespace AppBundle\EventListener;
use FOS\UserBundle\FOSUserEvents;
use FOS\UserBundle\Event\FormEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpFoundation\RedirectResponse;
use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
use Doctrine\ORM\EntityManager; //added
class UpdateOrCreateProfileSuccessListener implements EventSubscriberInterface
{
private $router;
public function __construct(UrlGeneratorInterface $router, EntityManager $em)
{
$this->router = $router;
$this->em = $em; //added
}
/**
* {#inheritDoc}
*/
public static function getSubscribedEvents()
{
return array(
FOSUserEvents::REGISTRATION_COMPLETED => array('onUserCreatedorUpdated',-10),
FOSUserEvents::PROFILE_EDIT_COMPLETED => array('onUserCreatedorUpdated',-10),
);
}
public function onUserCreatedorUpdated(FilterUserResponseEvent $event)
{
$user = $event->getUser();
$code = $user->getLicense();
$em = $this->em;
$lastEvent = $em->getRepository('AppBundle:LicenseEvent')->getLastEvent($code);
$licenseEvent = new LicenseEvent();
// here I set all the fields accordingly, persist and flush
$url = $this->router->generate('fos_user_profile_show');
$event->setResponse(new RedirectResponse($url));
}
}
My service is like follows:
my_user.UpdateOrCreateProfileSuccess_Listener:
class: AppBundle\EventListener\UpdateOrCreateProfileSuccessListener
arguments: [#router, #doctrine.orm.entity_manager]
tags:
- { name: kernel.event_subscriber }
The listener is properly triggered, manages to create the connection to DB as expected, but gives me the following error
Catchable Fatal Error: Argument 1 passed to AppBundle\EventListener\UpdateOrCreateProfileSuccessListener::onUserCreatedorUpdated()
must be an instance of AppBundle\EventListener\FilterUserResponseEvent,
instance of FOS\UserBundle\Event\FilterUserResponseEvent given
I must be missing something very stupid...
Another question is: I don't want to change the redirect page, so that if the original page was the "email sent" (after a new user is created) let's go there, otherwise if it's a profile update show the profile page.