The index.php file is truncating the last three lines of code to get the sidebar and footer, which is throwing a syntax error.
The correct code is:
<?php get_sidebar(); ?>
<?php get_footer(); ?>
Each time I update it, it reverts after five or ten minutes.
I thought to log directly into my host and fix the problem there, but it looks right in there. I have no idea what's happening! Any thoughts would be appreciated.