Just one thing to point out that may be important in this. I know this might sound harsh, I'm just trying to be realistic.
Is the WTS really responsible for the abuse? If they knew of and covered up previous abuse by the same person or the person could only abuse you because of failure by the religion to protect you as they should then I think they would be guilty and have something to pay for but if your complaint is that they didn't punish the person enough after the fact then I think that is unlikely to be successful in any claim.
If, as The Search points out, that person went on to abuse someone else after they were aware of your abuse and because they failed to act to warn or protect others then that person would likely have more of a claim.
Would an employer by guilty for instance for not firing them or a library for not banning them? Believing the WTS has to hand out punishment is really re-living the belief that they hold the keys to salvation. They just don't. The WTS are not responsible for punishing people but they should be held to account for policies that put children at risk and allowing known abusers subsequent access to other children.
The courts hand out punishment and it sounds like the court found him guilty (you don't say what punishment he received - it sounded like there wasn't any prison time?)