Have you actually spoke to this person, or do they just leave messages? Once, for a 12 hour period, this guy kept calling me on my cell insisting I was his ex-wife. He kept calling me "Holly" and insisting he knew where I was and he was going to "get" me. He literally called me every 2 minutes from about 9pm in the evening until about 9am the morning. I had to keep answering it, because I didn't want it to roll to my voicemail and this guy to get my real name. He scared me. I finally called my cell phone carrier and they blocked his calls for me. Maybe that's an option for you if you can't get them to stop calling.