Ahem.
Posting of a PM is listed in the TOS as grounds for a ban! There is a reason they are called Private Messages, they are supposed to be PRIVATE.
If you receive a PM from someone who you don't want to converse with, just click on Leave Conversation at the top of the message.
If you no longer want to receive any messages from that member, then just add their user name to your ignore list.
That's kind of shitty.
First off, it's one thing if you solicit a private conversation and then reveal it. That makes you an asshole.
But when somebody is bombarding your ass with insulting PM's, and you tell them to stop, and they don't, and you didn't ask that person to message you at all, and your moderation software is so antiquated that even though it has a report button you can't see it or do anything about it, then sorry. You shouldn't be making any rules about it at all.
If you are powerless to regulate it, then you shouldn't have the ability to do it at all. End of story.
And adding someone to ignore is a serious step because not only does it stop them from PMing you, but you 'll never again see anything at all from them. Ever.
This forum's software in that regard is so antiquated it defies belief. Several times I've seen several people and been victim myself of thinking somebody has lost their mind when they're not in fact talking to you they're talking to somebody else you can't see posted.
Most reasonable softwares still show you that somebody you are ignoring has posted, but doesn't show you the actual text of the post unless you click on it. But at least that way you know they posted and can put two and two together and figure out that the post made were referencing what that person said, not you.
I just find it laughable that your solution to any and all things is ignore it. If someone is causing that many problems, and that particular individual is and everybody knows it, it should be that individual punished and banned for it, not the person receiving the abuse from that person.