1) Keep reporting these folks when they harass. Do not reply to their remarks as you may end up getting in trouble yourself. Just report.
2) This sounds serious enough to bring in the big guns. If this continues, I would send a PM (Private Message) to HomeForumMods. Include the PSN ID of the offender, the date, time, time zone and the details of the offense. Do this with each offender and each time it occurs.
3) Do not mention this to them. Do not even chat about the weather with them. Doing so may encouraged even more harassment.
4) When you encounter these folks, immediately put them on Ignore. At least for that time, they will not be able to communicate with you or get too close.
5) And if you have friends who witness this, they can help you by doing the same thing.
Go to your account settings and make it where only your friends can message u lol thats instantly blocking the entire playstation network of people, so theres your start, now....if your on home the ignore feature is nice and fast it take literally no time at all.
Then just make it where u cant recieve friend requests