Updateorcreate always create | How to use it?

I try to use updateOrCreate function in an observer. So i have this function :

 $transportpropremoyenaller = Transport::updateOrCreate(
        ['centre_id' => $gestionsejour->centre_id, 'allerouretour' => 
'Aller', 'date' => $gestionsejour->datedebut],
        ['ville' =>  \Config::get('constants.transport.0'), 'tarif' => '0']
    );

I use this function in GestionsejourObserver like that :

 public function created(Gestionsejour $gestionsejour)
{
    return $this->addtransportpropremoyen($gestionsejour);
}

When i create a new object updateOrCreate never update and always create a new one.

Gestionsejour model is:

 protected $fillable = [
    'datefin',
    'user_id',
    'agrement',
    'centre_id',
    'datedebut',
    'created_at',
    'updated_at',
    'deleted_at',
    'dureesejour',
    'periodesejour',
    'complet',
];

public function centre()
{
    return $this->belongsTo(Centre::class, 'centre_id');
}

public function getDatedebutAttribute($value)
{
    return $value ? Carbon::parse($value)->format(config('panel.date_format')) : null;
}

public function setDatedebutAttribute($value)
{
    $this->attributes['datedebut'] = $value ? Carbon::createFromFormat(config('panel.date_format'), $value)->format('Y-m-d') : null;
}

public function getDatefinAttribute($value)
{
    return $value ? Carbon::parse($value)->format(config('panel.date_format')) : null;
}

public function setDatefinAttribute($value)
{
    $this->attributes['datefin'] = $value ? Carbon::createFromFormat(config('panel.date_format'), $value)->format('Y-m-d') : null;
}

public function user()
{
    return $this->belongsTo(User::class, 'user_id');
}

Myabe it's not possible to send 3 attributes or there is a problem with date. I don't know. I'm reading laravel doc but don't understand what is the problem in this simple function.

via Chebli Mohamed