Can't reinstall Visual Composer – major error for my site

For http://armchairarcade.com/perspectives/ I’m trying to debug issues on my site and deleted Visual Composer. Now I can’t get it back and it’s causing the style sheets on various pages to break. Can you kindly assist? (I’ll post login details in the next message)

Also, the reason why I was trying to debug is that after the last series of updates, I no longer have ATTACHMENT DISPLAY SETTINGS under INSERT MEDIA when I try to insert an image.

Finally, using System Diagnostics, I have the following error message:

Fatal error: Call to undefined function wc_let_to_num() in /home1/buckman/public_html/perspectives/wp-content/themes/HighendWP/admin/hb-panel/diagnostics.php on line 108