Pagination not working on page of posts from a particular category

Hi,
I have a page set up to display posts from a certain category. The posts display fine but the pagination links at the bottom of the page don’t allow you to view the next set of posts. When you hit it, it just brings up the same posts again, while saying ‘/page/2/’ in the url.

Any help is much appreciated. Here is the markup.

<?php
/*
Template Name: Events
*/
?>

<?php get_header('single'); ?>

	<div id="primary" class="content-area">
		<div id="content" class="site-content" role="main">
		<!-- .blog-container -->
		<div class="blog-container">
		<header style="margin-bottom: 20px;" class="blog-header">
			<h1 class="txt-wht">Latest In-store Events</h1>
			<div class="search-form"><?php echo do_shortcode("[wpbsearch]"); ?></div>
		</header>
		<?php if ( have_posts() ) : ?>

			<?php /* The loop */ ?>
			<?php query_posts( 'category_name=instore-events' ); ?>
			<?php while ( have_posts() ) : the_post(); ?>
				<div class="blog-wrapper">
                    <div class="blog-post">
                        <!-- featured image -->
                        <div class="post-thumbnail"><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_post_thumbnail( $size, $attr ); ?></a></div>
                        <!-- /featured image -->

                        <!-- excerpt -->
                        <div class="blog-excerpt">
                        <h3><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></h3>
                        <span style="font-weight:bold;"><?php the_field('date'); ?></span>
                        <?php wpe_excerpt('wpe_excerptlength_index', 'wpe_excerptmore'); ?>
                        </div>
                        <!-- /excerpt -->
                    </div>
                    <!-- /blog-post -->
				</div>
				<!-- /blog-wrapper -->
			<?php endwhile; ?>

			<?php else : ?>
			<?php get_template_part( 'content', 'none' ); ?>
			<?php endif; ?>

        </div>
        <!-- .blog-container -->
        <!-- pagination -->
			<div class="pagination">
			<div class="nav-next alignleft"><?php previous_posts_link( 'Newer posts' ); ?></div>
			<div class="nav-previous alignright"><?php next_posts_link( 'Older posts' ); ?></div>
            </div>
            <!-- /pagination -->
		</div><!-- #content -->
	</div><!-- #primary -->

<?php get_footer(); ?>