Testimonial Content Not Loading

I’m using the theme Zap Lite which implements your plugin. When I use the shortcode they provide, it loads author and company fields, but not the actual testimonials. Here’s their function:

function zap_testimonial_carousel_shortcode( $atts, $content = null ) {
	extract( shortcode_atts( array(
		'category' => '',
		'limit'    => '-1'
	), $atts ) );
	$output = '';

	query_posts(array(
		'post_type' => 'testimonial',
		'posts_per_page' => $limit,
		'easy-testimonial-category' => $category,
		'post_status' => 'publish'

	));

	if ( !have_posts() ) {
		wp_reset_query();
		wp_reset_postdata();
		return;
	}

	$output = '
	<div class="testimonial-wrapper">
		<div id="testimonial-container">';

			while(have_posts()) {
				the_post();

				$output .= '
				<div class="testimonial-item">
					<div class="testimonial-data">
						<p class="testimonial-content paint-area paint-area--text"><span class="testimonial-quote icon-quote-left"></span>'.get_the_excerpt().'</p>';
						if ( get_post_meta(get_the_ID(), '_ikcf_client', true) ) {
							$output .= '<span class="testimonial-author paint-area paint-area--text">'.get_post_meta(get_the_ID(), '_ikcf_client', true).'</span>';
						}
						if ( get_post_meta(get_the_ID(), '_ikcf_position', true) ) {
							$output .= '<span class="testimonial-company paint-area paint-area--text">'.get_post_meta(get_the_ID(), '_ikcf_position', true).'</span>';
						}
						$output .= '
					</div>
					<div class="testimonial-image">';
						$img = wp_get_attachment_image_src(get_post_thumbnail_id(), 'full');
						if ( !empty($img['0']) ) {
							$output .= '<img src="'.$img['0'].'" class="attachment-tbtestimonial_thumbnail wp-post-image" alt="testimonial-image">';
						}
					$output .= '
					</div>
					<div class="clearfix"></div>
				</div>';
			}

	$output .= '</div><div class="testimonial-pagination"></div></div>';

	wp_reset_query();
	wp_reset_postdata();

	return $output;
}

It appears that get_the_excerpt is empty. Any idea what’s going on? Tyia.