Excerpt "Read more" modifying

Hello!

I have problems modifying Read More for excerpt.
I have following code to display posts:

<?php
$args = array( 'numberposts' => 4,'post_type' => 'offers' );
$lastposts = get_posts( $args );
foreach($lastposts as $post) : setup_postdata($post); ?>
<h3><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h3>
<?php the_excerpt(); ?>
<?php endforeach; ?>

And I am trying to use this filter:

function custom_excerpt_more( $more ) {
	return '[.....]';
}
add_filter( 'excerpt_more', 'custom_excerpt_more' );

But nothing happens 🙁 Where’s a problem?