Actually, Square Enix does a great job with dealing with harassment. I personally have never needed to actually report someone for harassment because I find the Blacklist function to be an effective tool, but the people I know who have gone through the effort tell me that the issue was dealt with quickly. I have never heard of an instance where a person was using bad language, or name calling, and Square Enix didn't do something about it.
I honestly don't see the big deal about someone following me around. I've had it happen and I just ignored it. For me, it wasn't a big deal. However, in instances where it does become an issue then why not try teleporting? Though, I personally wouldn't bother as that will only let the person know they've gotten under my skin and give them a reason to continue that behavior. If someone spam emotes at you, after you've blocklisted them, then Square Enix will take action because of their strong stance against spamming. I've seen people suspended because of those annoying picture spams in dungeons.
I suspect that if the person is following you around in game, they are probably looking you up online.. and they are aware of at least some of the public complaints you've made about this. Speaking as someone who has dealt with trolls on the internet for a long while, I can tell you all you are doing right now is feeding him/her. They thrive on creating drama.
Also, someone else mentioned it but It should be mentioned again. Sending a hundred tickets definitely does not help your cause. As someone who worked in a position to resolve tickets, I can tell you that people who spammed tickets for the same issue became well known around the office and all their issues were seen as frivolous complaints. I would not be surprised if you've got a bias against you with the rank and file.