Have you tried Kies 3 on your PC? Sometimes when there is no OTA (Over The Air) update from the phone there is an update via Kies.

Kies 3 can be downloaded free from Samsung, here is the US site :
Kies

 

I second Kies 3. It updates phones that are even rooted that OTA won't touch.

 

How is it not working, does it connect to your device at all?

 

In my experience the Note 3 was so much better on Jelly Bean and I regret updating to Kit Kat. I recently updated using Kies and it destroyed my previously awesome battery life and gives me 2-3 random reboots per day. This phone was a dream on Jelly Bean but once you update their is no way back.

I hope the same thing doesn't happen to the Note 4 when L gets released.