I don't know that I can help, but I can say I know what it feels like (or felt like, in my case) to have an Arachnoid Cyst!
I had a large posterior fossa arachnoid cyst, and had many of the symptoms you have, but I had cyst fenestration surgery a few years ago, and that was successful...so far.
All I can say is to try and find a good Neurosurgeon that will help you, if they won't, then keep on looking for one that will. I can't reccomend any neurosurgeons, because I live in Aust. You shouldn't have to put up with all those horrible symptoms for that long. Some sound quite scary to me, because I haven't experienced seizures or paralysis. But the pain, pressure, dizziness and balance problems are bad enough to have to try and cope with!

~Jaime~