Getting Custom Posts with Custom Taxonomy

by

Your taxonomy Query is worng. please try something like that:

$args = array(
    'post_type' => 'contact',
    'tax_query' => array(
        array(
            'taxonomy' => 'abteilung',
            'field'    => 'term_id',
            'terms'    => '29',
        ),
    ),
);