How do get rid of an online leeche?

This leeche been at it for 4years. Sometimes he is a troll. People continue to feed him as if he is a normal user. Please help. He is a gay african american. Deeply insecure. I'm a african american girl. It's like I've been chewed up and spit out. People are not recognizing there is a bad situation going on. I'm not an expert on how to deal with these types of strangers.