If everything you say is true, then at this point your most sensible option is to simply ignore your "stalker" and concentrate on what makes you happy about the site, or else move on to one where you have a less stressful time.
I assume you mean a site such as Stack Exchange, or reddit, or something similar where user content can be voted up or down. Such sites are run privately, and within certain limits, are allowed to make their own rules about such voting. If you have already made your case to the users designated to moderate said site, and they have concluded that there's nothing they can do about it, then your options are limited.
Also, keep in mind that the voting activities on such sites is usually kept private, and for very good reason. It's entirely possible that the reason nothing is being done to "protect" your content is that the moderators have investigated and see nothing actionable. It's possible that you are overreacting to the usual ebb and flow of voting activity on sites. All user-moderated sites have people who just disagree with everything to be contrary, and since they are anonymous, they can do it. You can't control this, or stop it, and trying to do so will only frustrate both you and the moderators you keep asking for help.
In particular, one thing you should not do is to continue to publicly call out such activity where other users can see it. Since other users can't really do anything to help you, this will mostly come off as attempts to garner sympathy, or to "throw a tantrum". Remember, everyone else suffers from the same kind of random anonymous voting patterns as you do. It's a natural part of such sites. Attempting to somehow single yourself out as a "victim" of such activity is a bad way to gain support from the group you're participating in, as most of them will have already learned to "just deal with it".
All communities have "unwritten rules" of behavior; by making it clear that you either cannot or will not live within those "unwritten rules" you are actively isolating yourself from said community. That is only going to increasingly make it stressful and frustrating for you to participate in said community.
As long as you don't break the rules of said community, of course, you have every right to air your grievances. But if your goal, as you state, is to "just want to be left alone", then really your best option is to find a community who's unwritten rules you can deal with, because clearly whichever one you are participating in isn't working for you.