Blue Prints For Sand Rail Problem With Neighbours Wall?

Problem with neighbours wall? - blue prints for sand rail

Hello
my new next-door neighbor built a 30 meter high wall between the two properties were allegedly stone sand for construction and was in the original plans has shown us, this changed when we were on vacation, they changed to concrete blocks, so that if we are them and they told me they loved, and next week is on the wall at the side of us that we must play our part too? plz need to know so much hatred had other problems with them so