blog next post and last post links not working

Hello,

I’m wondering how I may be able to get someone’s attention with my post.
I have gone back to the designer of our site and he has also referred to wordpress support with no success.

Here is the problem code:

</article>
<div id=”navleft” class=”nav-single btn”><?php previous_post_link(‘%link’,’ ← Last post’); ?></div>
<div id=”navright” class=”nav-single btn”><?php next_post_link(‘%link’,’Next post →’);?></div>
<div class=”clear”></div>
<?php endwhile; else: ?>

Our page is at https://www.garbiz.ca/blog:

the last post and next post links don’t work properly.

Someone please help! Thank you in advance.