As far as the refund for it goes, you will need to provide access to your Joomla backend to the developers so they can try to fix this / install the extension for you and determine wheter you're eligible for a refund or not. I didn't want to do this, but I probably would have gotten a refund if I had given them access (obviously I can't be sure about this).
All in all, 2/5 because eventhough I can understand their point of view, I'm still very dissatisfied with the way things ended up.
Sorry this did not work out. There were various sides to this support-issue that made us believe that Dynamic404 was not causing the problems. First of all, Dynamic404 simply is not active when you reach a normal page, it only reacts on 404-errors. So if a normal page was working before, and suddenly it no longer was, most likely something else changed. Removing Dynamic404 makes sure that no Dynamic404 functionality is present anymore. This supports our belief that this problem was actually related to something else - perhaps enabling "mod_rewrite" in the Global Configuration while not having read the instructions on the htaccess-file?
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