Hi Lisa-
Sorry to hear about the issues, we’ll do our best to help you out.
I wasn’t familiar with IDX, but after some searching and checking out your site, I’m assuming you mean the IDX Broker Real Estate software.
If I understand it correctly, this software updates your website with current real estate listings, and if it’s not working correctly I’d have to guess that it’s using a REST API to make updates to your site, and W3 Total Cache is somehow affecting the API.
Can you take a look at Performance > Page Cache and check to see if you’re caching the REST API? You’ll find it in the section in between Purge Policy and Advanced.
It’s also possible that the IDX Plugin has created a custom REST API endpoint, and we’d need to manually add that to your Never cache the following pages option. If possible, can you reach out to IDX Support and ask them what their REST endpoint URL is?