SocialEngine hook does not work - hook

Question

I have created a new module to add a new step to the signup process to get the user's phone number. Everything works fine, except the fact that after the signup, I need to grab the phone number I have received in my specific step and add it to the users table. For this purpose, I have added a hook in my module's manifest file as follows to be triggered after signup completes:
<?php
return array(
'package' =>
array(
'type' => 'module',
'name' => 'advancedsmsplugin',
'version' => '4.0.0',
'sku' => 'com.company.sms',
'path' => 'application/modules/Advancedsmsplugin',
'title' => 'Advanced SMS Plugin',
'description' => 'Advanced SMS Plugin',
'author' => 'Company Ltd.',
'callback' =>
array(
'class' => 'Engine_Package_Installer_Module',
),
'actions' =>
array(
0 => 'install',
1 => 'upgrade',
2 => 'refresh',
3 => 'enable',
4 => 'disable',
),
'directories' =>
array(
0 => 'application/modules/Advancedsmsplugin',
),
'files' =>
array(
0 => 'application/languages/en/advancedsmsplugin.csv',
1 => 'application/modules/User/Form/Signup/Phone.php',
2 => 'application/modules/User/Plugin/Signup/Phone.php',
),
),
'hooks' => array(
array(
'event' => 'onUserCreateAfter',
'resource' => 'User_Plugin_Phone',
),
),
);
?>
I have also created the class that I named in the hook namely User_Plugin_Phone and saved it as application/modules/user/Plugin/Phone.php.
class User_Plugin_Phone extends Core_Plugin_Abstract {
public function onUserCreateAfter($event) {
echo '<script>console.log("Inside User_Plugin_Phone::onUserCreateAfter");</script>';
echo '<script>alert("Inside User_Plugin_Phone: onUserCreateAfter");</script>';
$payload = $event->getPayload();
}
}
But, logs show that the hook is not triggered at all. I have checked this and this, and I think I have followed them correctly. Any ideas why this does not work]?