My sister hates me as i was possessive. She left me! Pls help me to get her back...pls?

You sound completely obsessed with this girl, and even if you were her lover you STILL would not have any right to be acting the way you do. But you arent even her lover so I dont know where you get the idea that your behavior is ok? Spying on her activity, telling her who she can and cannot speak with. Interfering by contacting her family in regards to her activity or her lack of communication with you. Seriously, dude. Nobody needs a person like this in their life. You dont respect her, her decisions, or her privacy. Its really kind of scary and I dont blame her for cutting you off. You need counseling to figure out your issues man.