Can you collect proof? I'm no lawyer, but I know this kind of thing can take its toll, even if they never get physical. (And we never know if it will become physical, unless it does.) Emotional distraught often causes physical ailments. Don't escalate by reacting, as tempting as that is, (bullies tend to like the counteract, so you'd be playing into their hands), but get creative and prove your case.
When you can get to that point, you have another decision to make. Sadly, that decision needs to be based on your emotional and physical health at that time. Then you decide if you take it back to the landlord to handle, take them to small claims court (assuming they are destroying your property in the harassment - bullies like to act out physically, even if it's not an attack on you), or get a lawyer.
I know you're probably wondering what small claims court can do for you. I was bullied by neighbors once, and took the damages they inflicted on my property as a small claims court case. When we got there, they announced they were moving, and the judge told them this would be revisited, if they didn't. Apparently, this was a lifestyle to them, so they saw the handwriting on the wall, even if I didn't.
But, the moral of the story is, you can do something, besides retaliate or be a victim. (And, you're not a victim. You're a target. Victims don't "fight back.") It will take time, but you'll feel better for standing up for yourself.
Lynn