what action is appropriate..?

Someone that I never know a suddenly want to see me face to face to prove who the real me. I was surprised by the invitation. That People also accuse me was his girlfriend, who disappeared. I decided to not see this people because I was worried something happened to me. I also no longer respond to all email sent to me. The person may seem to threaten and intimidate me. If I did not come to see him or find his girlfriend this people said to find me wherever I go. Not only that, these people are spying on the social space that I use to communicate with my friends. I feel very threatened. I have explained the real thing and say me and his girlfriend is not the same person but he still did not want to believe except I had to come see him. I certainly recognize his girlfriend once, but now we have lost contact. I do not know what to do anything coz account social of my friends applied once been used by man.This men also threatened me to bring this case to court and the police. I am married and I do not want this affecting my marriage. I had the greatest caution so as not to disturb me again, but this person never stops.
He also has hired a woman to smear my image through social websites. What is the most appropriate action I should do in this case ..? and what legal punishment commensurate to act like that ..? i was afraid..