iCloud files missing

I had transferred my iPhoto library with some other files to iCloud before giving my computer to Apple as it was having issues. To make sure I wouldn't lose my photos and other files I asked the technician if my photos and files would be safe in iCloud if they had to fix the hard drive, he said yes. I just picked up my computer today and they had to install a new hard drive, so I have to reinstall everything again. I went to open iCloud and there is nothing there! What happened to my files???