As we are a community platform, we thought it would be best to leverage that and "eat our own dog food" so to speak. As you've experienced, the community can be quite powerful and got you the right answer to your problem outside of our regular business hours. We also wanted to build a resource where common questions, like yours, are already answered can help give you a more immediate answer by using our search.
Additionally, no support has been lost, it has simply been moved. Technicians, like myself, still have access to your secure access details to your community in the Client Area, we can escalate topics to private tickets to have our developers investigate, and if you have private details you need to share, we can work around that to continue to assist you.
Overall, all who have been quick to dismiss this new change, have actual come back to say they really like it once they tried it. I would encourage you to give it more time as well 🙂 .
This would indicate that permissions on your server are preventing PHP from extracting and moving files as required as a part of the auto-upgrade process thus you need to perform manual upload. You can download the delta files from the upgrader and extract those to your computer, then upload these to your server, overwriting what is there. Then go to /admin/upgrade/ to complete the upgrader.
Regardless of how you upgrade, it would be advised to create a full backup (database and files).
Once you get your community back online, you will want to reach out to your hosting provider and ensure that all folders/files are owned by the proper user/group on your server. Then also ensure that proper permissions are applied to all folders/files.