Once that is done you need to reconnect all the USB devices via their cable just like they were connected before.
While it might seems very easy, this is a good solution and most of the time does the trick.
I would not have allowed the upgrade if the information they provided was accurate.
Its too bad Apple lied to me about the ability to revert/restore.
If it doesn't work, then you should think about disabling all the antivirus software as that might interfere with the restoration process.