Neighbor who likes to leave their dog outside without supervision

I live in an apartment complex in DTLA/Ktown and my neighbor always leaves their big ass pit/terrier mix outside their door attached to a questionable leash without supervision. I have a 10 pound small chihuahua mix (who is reactive and barks at everything like most chihuahuas) I always make sure their dog isn’t outside whenever I go to walk my dog because they’ll start barking at eachother which like a little stressful, not the end of the world, but the other day I was taking my dog inside from his walk and the neighbors dog is outside by herself and they start barking at eachother and the leash breaks and the dog comes charging at us like it’s gonna attack us. The neighbor comes out and grabs the dog before it’s able to get me or my dog luckily but i’m so scared that dogs gonna attack me or even worse my dog. The dog also lunges at me when it’s unsupervised now. I also see the neighbors taking the dog into our parking garage and back area without a leash at all. I know the neighbors have a cat so the dog isn’t inherently aggressive to small animals but you never know when they’ll decide they aren’t nice anymore also I’m not usually afraid of dogs (i’ve been bitten by many before) but this one genuinely scares me. What’s my best action plan because I would literally go crazy if anything happened to my dog and I want to continue to live at my apartment???