Scorned woman stalking

Omg this girl has got to stop. I’m dating her ex and she’s lost her mind over it. She now comes to my house and sits outside and texts my bf telling him that she sees we just got back. She says her grandma works at the courthouse so she knows her rights and she can sit wherever she wants including outside my house and I can’t do anything about it. I’m like, girl you’re crazy and doing too much. She’s already tried breaking us up with a bunch of lies and when that doesn’t work it’s this harassment. Is she tryna make me dump him or what?

Update: my bf’s reaction to her texts are a combination of confusion and disbelief like he can’t believe she’s acting this way, especially when she’s the one that got pissed and dumped him. He also seems concerned that I’ll get fed up and break up with him over her craziness. He can’t block her because they have a child.