Doug,
Achieving what you want is really quite simple - it's obvious that the company you hired doesn't have a good understanding of Zen Cart's architecture.
Five simple steps for what you want to do:
1. For the content you want at the top of your main page, just use the existing define main page system, with no changes - just edit the define_main_page in admin as normal.
2. For the content that you want to show at the bottom of your main page, create a new file includes/languages/english/html_includes/define_main_page_lower.php - you'll be able to edit the content of that from the Define Pages Editor in Admin.
3. Create a new file includes/extra_datafiles/main_page_definitions.php with this content:
Code:
<?php
define('FILENAME_DEFINE_MAIN_PAGE_LOWER', 'define_main_page_lower');
?>
4. Edit includes/modules/pages/index/header_php.php and add this line of code:
Code:
$define_main_page_lower = zen_get_file_directory(DIR_WS_LANGUAGES . $_SESSION['language'] . '/html_includes/', FILENAME_DEFINE_MAIN_PAGE_LOWER, 'false');
immediately below this line:
Code:
$define_page = zen_get_file_directory(DIR_WS_LANGUAGES . $_SESSION['language'] . '/html_includes/', FILENAME_DEFINE_MAIN_PAGE, 'false');
5. Make an override copy of includes/templates/template_default/templates/tpl_index_default.php and add this line of code immediately before the closing /div tag at the end of the file:
Code:
<div id="indexDefaultLowerContent" class="content"><?php require($define_main_page_lower); ?></div>