That totally stinks Angie!
I can't imagine having horrible neighbors like that. I have a guy beside me that's a little different but is nice enough. I am very fortunate, I suppose.
I really don't have any advice - altho I think that Electric fence Anna put up is a good start. Or the shrubs so that they can't get near the fence, but that would also need some upkeep.
I just can't imagine.....