Is what occurred between the young man and woman—a complete sexual relationship over the phone and internet—considered zina (unlawful sexual intercourse)? And what must they do to expiate their sins after repenting?

Emotional relationships between young men and women via the internet or phone are forbidden and reprehensible. What transpired between the questioner and the girl in this regard is a grave sin and figurative adultery, as the Prophet, peace and blessings be upon him, called it: "The adultery of the eyes is looking, and the adultery of the ears is listening, and the adultery of the tongue is speaking, and the adultery of the hand is seizing, and the adultery of the foot is stepping, and the heart yearns and desires, and the private parts affirm or deny that."

The expiation for this sin is sincere repentance, by abandoning the sin, regretting it, and resolving not to return to it, along with concealment and not publicizing it. The relationship with the girl must be severed, and one must repent to Allah, and take the initiative to marry if possible to protect oneself from sin.