Sorry to hear about your travails. I had the same problem, which resisted augmentin and everything else, and I faced surgery. Fortunately, I invented a way to remove a sinus infection without surgery. It uses salty water in a different way than you tried.
The pain behind your eyes indicates that the infection may possibly be in your sphenoid or frontal lobes, which are higher up in the head. When you put saline in your nose, it won't reach those sinuses, due to gravity, and it will be useless, as you have discovered. I invented the Flip-Turn Sinus Flush, which requires that you bend over, so that you USE gravity, instead of fighting it, and to get a lot of saline in there, not just a trickle.
http://www.medhelp.org/user_journals/show/2322
The Flip-Turn Sinus Flush is mildly risky, because you have to bend over to do it, preferably in a shower, but you can also do it outside on soft ground.
The first few times you try it, you may not get very much infected mucus out of your sinuses, because the saline sometimes needs to shrink the swollen passages to the upper sinuses first. After about 3 or 4 days, some nasty stuff should start flowing out. If it does, continue for about 7 more days. Once you wash out most of the infected mucus, your sinusitis has a good chance of clearing up. If it doesn't seem to help after the first 5 days, then you may want to start saving up for surgery.
If it does work, tell your surgeon I'm sorry.
Good luck. Persistance rules.