Structuring function with registration_errors hook

I created a plugin that adds a function to the registration process where the user info also gets added to an external db. The problem is that, when the function runs successfully i.e. user is able to be added to the external db, but the wordpress registration process returns and error, the user is still added to the external db. How can I structure this so that if there's an error on the Wordpress side or the external side, the user sees and error and nothing is added to any db.

Here's my code:

    function add_user_to_SF($errors, $sanitized_user_login, $user_email ) {
    global $SF_USERNAME;
    global $SF_PASSWORD;

    try {
      $mySforceConnection = new SforceEnterpriseClient();
      $mySoapClient = $mySforceConnection->createConnection(CD_PLUGIN_PATH . 'Toolkit/soapclient/enterprise.wsdl.xml');
      $mySFlogin = $mySforceConnection->login($SF_USERNAME, $SF_PASSWORD);

        $sObject = new stdclass();
        $sObject->FirstName = $_POST['user_login'];
        $sObject->LastName = $_POST['user_login'];
        $sObject->Email = $_POST['user_email'];

        $createResponse = $mySforceConnection->create(array($sObject), 'Contact');

        $ids = array();
            foreach ($createResponse as $createResult) {
                array_push($ids, $createResult->id);
            }

            } catch (Exception $e) {
              //echo $mySforceConnection->getLastRequest();
              //echo $e->faultstring;
              $errors->add( 'demo_error', __('<strong>ERROR</strong>: There is a Salesforce problem.','mydomain') );
              return $errors;
        }
              return $errors;
    }

    add_filter( 'registration_errors', 'add_user_to_SF', 10, 3 );