problems with _________17

i was playing a ghost mode and this guy called me a hacker every kill i got.i told him that i dont hack and he still did it then he started making it personal by insulting me and cursing at me so i left.then he followed me in another and started saying i was a known hacker wen he joined the room and said if my team didnt kik me they would get in trouble.this is really getting on my nerves and i demand some sort of punishment for this behavior.it has gotten to the point where i cant even make a ghost mode map since he always follows me what should i do??