Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
What you can do, to try to get the original version back again, depends upon whether your Joomla is running/hosted on a Windows server, or a Linux server or other OS.
On Windows, something called System Restore can put a system (the programs) and its applications back the way they used to be. It does not work well with Microsoft programs, but otherwise, it keeps the data files the same, and restores the program files to the way they were. This can work with a 'broken' program.
However, if you were doing other work on other programs, or on the Windows system, it is not a partial restore: It restores everything to the time-point, or 'Restore Point', that you invoke. Not just one program, or one sector of the programs.
If that is N/A, or cannot be done, then there may be other ways. Let me know, and I will advise you further as needed.
(A thought: do a File Scan or Disk Scan, of your files where your Joomla is hosted. All of them. It might find a file allocation error or similar corrupted file, to set straight, that is located at the '82 %' location of your failed updates... and make an update possible once again.)