Getting all custom posts with a certain category

Question

$blabla = new Query($args); should be
$blabla = new WP_Query($args);

UPDATE
Your actual code should be something like:

$args = array(
    'post_type'         => 'fb',
    'tax_query'         => array(
        array(
            'taxonomy' => 'fbcate_category',
            'field'    => 'id',
            'terms'    => '35',
        ),
    ),
    'order'             => 'DESC', 
    'posts_per_page'    => -1,
);

$posts_array = new WP_Query($args);

Where taxonomy is your taxonomy name.

Let me know how it goes.