How do I block people from sending personal messages to me?

[SWAT One]

Title.  There's a kid who thinks I'm the S&R and help board and keeps spamming me with "hi", "hiiiii" or other dumb stuff.

[Ad Bot]

[Lugnut]

There's a stuffload of settings under your profile.
Could you check there for settings that pertain to... I dunno, "personal messages"?

[SWAT One]

Thanks, should I lock, or leave open for resource?