Did you build this site yourself or did you hire someone to build it for you? If you hired someone to build it for you I suggest you contact them about getting it updated. There is no reason for CB to try and reach a ".listing" folder. There's something wrong with your site or you've something installed causing problems.
You keep saying your frontend goes down, but from doing what? Updating CB? Updating a plugin? If updating a plugin then what plugin? What are you doing to result in the frontend of your site going down and what does the frontend going down even mean? Just throws an error? A white page? You need to be specific.
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www.joomlapolis.com/services/installation
If you need help finding a Joomla expert I recommend the below.
www.idlwebinc.com/services/joomla-services