need advise..neighbor nmin nagpaayos ng bahay nskop amin

please help me,, yung neighbor namin nagpaayos ng 2nd flr at nasakop ung kapirasong lupa namin.. naaawa ako sa daddy ko kase ung roof ng bahay nya tinapyasan covering ung way na iskinita which is legally ours. now, nagreklamo ang tita ko sa kanila, and they said nagpaalam naman daw sila sa daddy ko.. Is that a valid reason para gawin un? sabi naman ng tita ko,"hindi lang naman sya ang may ari eh, hindi dapat kau nagpatayo dyan". Right now, on going prin ung construction nila.. And the worst, kapag umuulan, pumapasok ang water sa loob ng bahay ng daddy ko, as in sobrang basa.. Naaawa ako sa daddy ko, I want to know what can we do about this.. What case should we file and what is the chance if we fight for it? please help me...

file your complaint first at the bgy.