Harassment by ex boyfriend

I did not want to continue with my boyfriend because of his suspicious nature and some other reasons also. I told him many times that I dont want to continue with this relation but he always ended up blackmailing and harassing me calling on my parents numbers and abusing me. So I kept silent. But after suffering a lot I decided to leave him. He called my parents continuously using internet generated number and sent me my nude pics and threatened me that he will kill himself. He even called on my office landline and all the colleagues. he even made face FB and Instagram account with my name and started talking to all my cousins relatives and friends. Then I went to the Police station and he gave in written that he will not do such things again. After that he has again started texting my relatives defaming me everywhere. Talking to strangers with my name. I am tired of it. He is saying that I and mY family will face the consequences. I dont know what to do. If i go to the court It is a time taking process .