Tim, we have no problem issuing refunds where they are due, which we do on a constant basis.
That being said, we stand behind our products 100% of the time, and we have provided solutions for the error you've encountered which, to my knowledge, you have not yet tried. We do apologise for the time your staging site was down due to the update process, we should have warned you of such possible outcomes when asking for the login details. However, please do note that the reason we ask for a staging site is so that such things do not happen on live sites, thus affecting your business in any way.
We are also yet to receive a reply to our last email. We really hope you can look past the initial struggle and allow us to help you get our plugins set up correctly on your site.
As stated in my last email reply, what we can ask you to do right now is to uninstall all WP RSS Aggregator plugins on the staging site (remove them completely), then install the latest Core version, then install the add-ons again. The installation process should not have any defects this way and you'll have the latest versions installed.
Looking forward to a positive outcome.