I also been trying to upgrade for a couple of months until such time that I already stopped trying and just accepted the fact that I'm stocked with Windows. I installed all the updates, did a store reset, change different networks, via LAN, via Wi-Fi, I even used a Mobile Broadband.
But last night was just my luck. I installed the latest Windows updates. Updated the apps from Win Store and tried to click Win 8.1 update. It was unsuccessful of course. With frustration, I just opened my torrent app, left my PC running then went to bed. When I woke up, viola. The Windows 8.1 set up page. I don't even know what I did, or what or who updated it. Maybe its just luck. So my friends, just keep trying. Who knows? Maybe this is your lucky day.
My answers to the question?? HAVE A LITTLE FAITH AND KEEP TRYING