Getting rid of a boy whos threatening family

Assalamo Alaikum.
I am very worried. I am a female from faisalabad. I was doing a job and studying at college where male and females studied together. There a boy proposed to me and he started coming to my home too. He convinced me to marry him by sitting at my feet and giving wasty of Allah and Rasool. He was a Hajji and 5 times namazi. He belonged to jhang. He gradually involved me in himself. He even took me to commit zina. Now the situation is that I have refused him for marriage because of too much threats from his side. But he is still doing the same. I am very sad and cry for maffi from Allah. He is threatenning my brother and family to destroy us. He has already destroyed me but he is not controlling till now.

Please guide me what should I read and do to get rid of him. Some one online suggested to me to read daroor qaharia 100 times after asar namaz. I am following that. I say 5 times prayer now but never use to pray namaz when I was involved in this kabeera gunnah. Allah maaf karny wala or raheem hai. Main us zaat sy maafi ki umeed b rkhti hoon or hr lamha maafian mangti hoon. Lekin wo insan hamain bht by sakoon kr raha hai. khuda k liye kuch esa bta dain k wo hamara peecha chor dy.
Waiting for your kind reply.

Allah Hafiz
Duaon ki talib