public function validatePhoneNumber($phoneNumber, $verificationCode)
    {
        Piwik::checkUserIsNotAnonymous();

        $phoneNumbers = $this->retrievePhoneNumbers();

        if (isset($phoneNumbers[$phoneNumber])) {
            if ($verificationCode == $phoneNumbers[$phoneNumber]) {

                $phoneNumbers[$phoneNumber] = null;
                $this->savePhoneNumbers($phoneNumbers);
                return true;
            }
        }

        return false;
    }