Sky's Old House - Neighbor Crosses Property Line to Cut My Hedges!!!!

WHY?!?!?!?!?!?! Can't I just get 24 hours without some sort of drama at Sky's Old House? Currently the answer to that question is NO. But I am hoping someday in the near future we will be drama free. The latest. We have a neighbor right behind us that has a two story house. His home looks directly into our yard. So when we got the house we planted a row of hedges along our back wall to eventually give us privacy. A few months into owning the house we got a report from one of our workers that there was a man in our yard trimming a bush and when he spotted him the guy jumped back over the fence. We ask the neighbor about it and he apologizes saying that he had an agreement with the old owners that his gardener would occasionally trim the tree (according to other neighbors this is a lie). I explained that we own the home now and if he needs anything to reach out but to not enter our yard. I agree to trim a tree for him (at his cost) but tell him this would be an annual discussion and not a monthly one. He agreed and thanked me. On his way out he made a brief mention of how he thinks he owns some of the land on OUR SIDE of the wall where we planted the hedges. I told him I am not aware of that and for him to not touch our hedges and to reach out if he has any concerns. Of course his deal is that these trees and hedges block part of his ocean view. I then unfortunately hear from a neighbor about how they caught him in our yard poisoning a big bush right after we bought the house but hadn't started construction yet. We figured that now he knew the homeowners were present he would knock that crap off. About 8 months go by and we don't hear anything so I figure this guy is happy with out new arrangement. Sunday we get a random voicemail from him asking us to sign a form acknowledging that he actually owns the strip of land where we planted our hedges. Like I would ever f***ing sign something like that! We thought it was strange all of a sudden for him to call, but I figured I would deal with it later. Yesterday the hubby runs into our cool neighbors yesterday and they show him video where they were yelling at the guy Saturday morning (we were out of town for a funeral) when they saw him on a ladder in his yard topping our hedges. Homie was not just cutting a few branches growing towards his yard (which would be fine). He was trying to cut the tops off to "preserve" his view. Looks like he only really got to one before my neighbors scared him away. So now it looks like we got to pay $$$$ to get a survey done and legally document where our property line is. I also talked to a police officer friend about the best next steps. So frustrating. When will people learn that they do not own the air/view over other people's homes!!!!!