Is the damage he's causing on the footpath? Cause the footpath doesn't belong to you so you have no right to complain, if it's in your yard, then yes, you could complain. Technically your mail box should be totally accessible from the footpath, he shouldn't have to go into your yard to deliver mail. If he does have to, he could request the mail box be shifted. I suppose to have to stop and back up for every mail box could become pretty annoying and time consuming on a whole mail run. Hope he's not a Newman!