Blackmail and mental stress by the co-owners of my flat

Myself and my mom have got new flat one and half year ago. Initially for 8 months - 1 year everything looked fine except few misunderstanding. After one more person added to the flat who is also a owner (Who first bought the flat - was in Singapore and returned now). Now im going though a lot of pressure because of them. I was not ready to give bribe for few things and they asked me to file case against our builder which i was not comfortable. Since i dint do the above they started to blackmail that no car parking area will be allocated for me (For which i have paid to my builder). For the common works they do, they are not providing any bills but just asking for money. Since i told ill nt pay till proper bill comes or proper calculations are done they are blackmailing as my water valve will b closed. They also use abusive words which i cant tolerate. These are creating mental stress and leading me to take wrong decisions. Please advice me if i should raise a complain against them.