Customization of search result on Job Listing

Hi,
I’ve tried to customize the search result text by word press default function..

remove_action( ‘job_manager_ajax_get_listings’, ‘get_listings’ );
add_action( ‘job_manager_ajax_get_listings’, ‘custom_get_listing’ );

function custom_get_listing(){
//my stuff
}

but it seem the remove_action is not working on job manager, So can you clarify on how can we override the function. If wp-job-manager function cannot be override by this way then how can we customize the wp-job-manager function.
Thank You.

Plugin Url: https://wordpress.org/plugins/wp-job-manager/