In the begining there is a guy that wants to find a good job and when he goes home, his mother is very sick and when he goes to buy the medicine, it's very expensive and he has no money. Then he works out how to get the money: he and his 2 friends (I think a woman and a man, one I think takes drugs) kidnap the daughter of a rich family and they take her hostage in the vacation house this rich family uses in the summer.
After 3 quarters of this film, you understand that this daughter's family have a servant that is the dad of the guy that kidnapped their daughter and blackmails them for money. He has a Zippo to light cigarettes and when she is kidnapped, she listens to the Zippo and in the end of the film, almost understands that he was her kidnapper - but the whole thing went successfully and if I'm not wrong, he kills all his friends.
Summary: Son of a poor family that has a sick mother and his father works for this rich family kidnaps their daughter to blackmail them for money and it's a success. I think it's from about 5 years ago or so.