How do you deal with people who are determined to make your life miserable? Lol

I knew someone on EP, she's nice and a good person... but, every time we talk, it's all about "how she's worthless and nobody cares about her etc". I do like to listen to people's problems but I also can't stand attention seekers that much... and it'd be rude to stop replying to her. So, what would you do?