Add BP PM remove mail message

Hi,
to do that you would need to first get the WPAdverts BP integration https://wpadverts.com/extensions/buddypress-integration/

This will add a send private message button on the Ad details page, if you additionally want to hide other contact options then you can do that by adding the code below in your theme functions.php file

add_action( "wp", function() {
  remove_action( 'adverts_tpl_single_bottom', 'adverts_single_contact_information' );
  remove_action( 'adverts_tpl_single_bottom', 'adext_contact_form' );
});