public function save()
    {
        $collection = $this->getContactsCollection();

        try {
            $contractSaved = true;
            $contactsSaved = $collection->save();

            if ($this->getContract() !== null) {
                $this->getContract()->save();
            }

            return $contactsSaved && $contractSaved;
        } catch (ResponseErrorException $e) {
            return $e->getMessage();
        }
    }