Friends....real, or just using you?

Ever had a 'friend' that totally fucked up and you didn't know how to tell them that you never wanted to speak to them again? I just don't know how to go about it without being mean. I guess that is what she deserves after STEALING and LYING....ahhhhhhhhhhh....but it is not in my nature to be a mean person. More later...gotta figger this one out! grrrrrrr :(