Read the EULA, you don't have a fighting chance. They have you by the balls no matter what your argument. If you tried to sue, the first thing the judge would ask you is what were you suspended for?
Well, I was hacking of course........
Hmmm, were you aware that was against Sony's rules in which you accepted when you clicked on "Accept" ?
Sony has the right to ban or suspend your account for any reason they choose. Hell, for no reason at all if they choose. You do not own your characters, they are not yours. You are simply leasing them from Sony for your own enjoyment. They can take it all back whenever and for whatever they see fit.
It sux yes, but that is basically how it works.
Have you ever read alot of EULA's? Microsoft even had to go so far as to claim they are not responsible for death or injury from the use of any of their software ROFL.