M.O.
My 17 year old daughter has a "friend" like that. Best thing, I think is to just let go, as much as it might bother you, sometimes kids just grow apart. Also , in my case, the family is related to us (distantly), and we have always been very close, vacationed together, etc. The other girl is actually mean to my daughter, and spreads false rumors. It was very hard for me not to call her mother, but I resisted. I think she is jealous because my daughter has a ton of real friends, and she doesn't, despite having everything else in life handed to her on a silver platter.