Slave Mail (2010)

Kayo, a college student, is devastated when her best friend Emi steals her boyfriend. In a moment of rage, she thinks, I’ll kill her!—not realizing that this fleeting thought will set off a terrifying chain of events. Suddenly, she receives a mysterious email: You are now a slave. When she tries to resist, supernatural occurrences strike. But the consequences of disobedience are fatal. Yet, the so-called "slave commands" she receives are not for torture or punishment—they are disturbingly erotic in nature.