First of all , who is this person and why is he targeting you? There are many online resources for help with stalking problems depending on the content of his messages and the consistency in which he bothers you, he may be prosecuted. check the laws in your state! I had a problem with cyber stalking in which the guy was e-mailing and changing his Sns. I sent him a warning in e-mail after talking with a detective and told him to not write to me again. it worked. however he started pming me under different yahoo aliases , but Y! tunnel pro took care of that problem and has worked wonderfully. I surely know how distressing this is for you. I hope this helped , good luck and take care!