TBH that sounds quite a lot more petty than somebody moving something that was put over their property line without their permission, then repeated moved back over their property line without speaking to them.
Well, as far as I can see from the photo, the actual mounting is not on the bloke’s side of the property line, and if the set-up is anything like mine, ie an inverted ‘U’-shaped tube held in place by four bolts, and the dish the same, it means 180 degrees of horizontal adjustment, so my suggestion is perfectly valid, and exactly what a competent installer would do – no need to re-drill and re-fit elsewhere, just swing the dish to the left, away from the property line, then swivel the dish back to align with the satellite.
He will have no argument about the edge of the dish overlapping his property line, which is just petty, and if it intruding into his line of sight on one side, tough. From what I can see, it could go further to the right without causing an issue with the dish being swivelled around anyway.