I know.
bottom line: OP needs to meet his neighbor and talk to him about the situation. It's amazing that such a simple solution would elude the OP. Instead, he looks to legal avenues as to who is required to perform the work.
Sometimes I really miss the old days where, rather than what happened here, you would go across the street and say "hey, I see our mailboxes got run over. Since I'm not real good with tools, what would it take to have you put my mailbox back the way it was. How about some grilled chicken and a beer at my place?"