Border Wars?

I haven't been to the garden for a couple of days. It's going to rain tonight, but I wanted to water with plant food to help my peppers which are really stumpy. I noticed one of my sunflowers that is supposed to get 10+ feet tall has bloomed at 6 feet and the sunflowers next to it were also ready to blossom and were turning kind of yellow.

All of the leaves on one side of the plants were cut off. I'm certain it was Valentina. First she's upset about the wild bird feeder, which I took down. Then the thistle feeder was knocked down. Now the leaves are cut off my sunflowers. Yes, the leaves did hang over the "border," but that happens all over the place. Mr Tse and Anatoli have plants that hang over the border, but mine were cut.

I understand that the lower leaves may have been hanging over their plants, but how does a leaf that is 5 feet in the air bothering a plant that is 15 inches tall.

I think I would take this better if they would have talked to me first. I feel really disrespected. When I came in, I called their apartment and left a message. Ticked as hell, I was tempted to trim all of their stuff hanging over the border - bushy flowers and onions that haven't been trimmed, but I'm above that. (I think?) Good fences make good neighbors, so I've decided to get some fence to take care of that part of the boundary. Also, I re-hung the wild birdfeeder. So there.