Классы композитора не загружаются автоматически с помощью библиотеки php-api Adyen?

Я пытаюсь заставить работать php-api-библиотеку Adyen, но я получаю сообщение:
Неустранимая ошибка: класс «Сервис \ Оплата» не найден

Сообщение об ошибке заставляет меня верить, что оплата класса не загружается, но как мне убедиться / исправить это ?? Я думал, что композитор сделает работу.

Я делаю на локальный XAMPP (Mac)
— Я установил с композитором
— простой test.php

>    composer require adyen/php-api-library Using version ^1.5 for
> adyen/php-api-library ./composer.json has been created Loading
> composer repositories with package information Updating dependencies
> (including require-dev) Package operations: 3 installs, 0 updates, 0
> removals
>   - Installing psr/log (1.0.2): Loading from cache
>   - Installing monolog/monolog (1.24.0): Downloading (100%)
>   - Installing adyen/php-api-library (1.5.3): Downloading (100%)          monolog/monolog suggests installing aws/aws-sdk-php (Allow sending log
> messages to AWS services like DynamoDB) monolog/monolog suggests
> installing doctrine/couchdb (Allow sending log messages to a CouchDB
> server) monolog/monolog suggests installing ext-amqp (Allow sending
> log messages to an AMQP server (1.0+ required)) monolog/monolog
> suggests installing ext-mongo (Allow sending log messages to a MongoDB
> server) monolog/monolog suggests installing graylog2/gelf-php (Allow
> sending log messages to a GrayLog2 server) monolog/monolog suggests
> installing mongodb/mongodb (Allow sending log messages to a MongoDB
> server via PHP Driver) monolog/monolog suggests installing
> php-amqplib/php-amqplib (Allow sending log messages to an AMQP server
> using php-amqplib) monolog/monolog suggests installing
> php-console/php-console (Allow sending log messages to Google Chrome)
> monolog/monolog suggests installing rollbar/rollbar (Allow sending log
> messages to Rollbar) monolog/monolog suggests installing
> ruflin/elastica (Allow sending log messages to an Elastic Search
> server) monolog/monolog suggests installing sentry/sentry (Allow
> sending log messages to a Sentry server) Writing lock file Generating
> autoload files

test.php

require __DIR__ . '/vendor/autoload.php';

$client = new \Adyen\Client();
$client->setApplicationName("Adyen PHP Api Library Example");
$client->setUsername("xxxx");
$client->setPassword("xxxxx");
$client->setXApiKey("xxxxxxxxxxx");
$client->setEnvironment(\Adyen\Environment::TEST);

$service = new Service\Payment($client);

$json = '{
"card": {
"number": "4111111111111111",
"expiryMonth": "03",
"expiryYear": "2030",
"cvc": "737",
"holderName": "John Smith"},
"amount": {
"value": 1500,
"currency": "EUR"},
"reference": "payment-test",
"merchantAccount": "ourshopcom"}';

$params = json_decode($json, true);

$result = $service->authorise($params);