Records insert POST with Guzzle returns 200 with no response

The getToken() function works fine. I have no problems to get a repsonse for '/crm/v2.1/settings/fields'

Following some snippets form my workflow for the POST Record

use GuzzleHttp\Client;

$options = [
        'headers' => [
            'Authorization' => 'Zoho-oauthtoken ' . $this->getToken()
        ],
        'json'    => [
            'data' => [
                [
                    'Anrede'        => '-None-',
                    'First_Name'    => '(API TEST)',
                    'Zweiter_Name'  => '(API TEST)',
                    'Last_Name'     => '(API TEST)',
                    'Date_of_Birth' => $dateTimeObject->format('d-m-Y'),
                    'Account_Name'  => '',
                    'Department'    => '',
                    'Position'      => '',
                    'Email'         => '',
                    'Phone'         => '',
                    'Mobile'        => '',
                    'Fax'           => '',
                ],
            ]
        ]
    ];

$client = new Client(['base_uri' => 'https://www.zohoapis.eu']);

$uri = '/crm/2.1/Contacts';

$response = $client->get($uri, $options);

$response = json_decode($response->getBody()->getContents(), true);

When i dump the $espone after all that steps, I get null but status code is 200