Retreive files after Windows 10 upgrade

Hello,
I recently updated to windows 10 and nothing worked, but I could retrieve my files from the windows.old folder.
Since nothing else was working, I thought it would be best to try to restore to windows 8 as I was happy with it.
I did this with the promise that 'this will not affect your personal files', now I have no documents anywhere. I have tried to look this up, I've looked in 'windows.old' folder and again there is nothing there. My files are extremely important to me and I really really need them back. I was on hold with your customer service department for half an hour, after hours of searching online for help, only for them to tell me that I'd have to pay $99 for support on the matter.
Please help me get my documents back.