I had the same problem with my LG G2 and im afraid to say but its 90% the digitizer .It has to do with the cable that connects it to the screen.The fact that your half screen worked,it is because a part ofthe cable cut or distorted in general .If you are lucky a good repair shop could save the cable.
On the other hand your digitizer costs about "6 to 7 euros "on ebay and the fitting shouldnt be more that 20 -30 eur.