I don't know the full story (apologies if it is on a different thread) and it appears you are frustrated with your neighbours for previous actions, some of which may be fully justified.
My only advice would be, don't cut your nose off to spite your face - neighbours can cause significant issues both during the build and whilst you're living there - I know I could do without that added stress. Maybe a 30 min conversation is worthwhile even if you end up with the same outcome as now - nothing to lose?