Bring it to their attention that they are making 你 feel badly. If they are true friends, they will apologize and try to rectify the situation. I am not sure exactly what took place, but they may not have known that they were offending you.
However, if they continue to act unfavourably, find someone else to be 老友记 with. There is no reason for good 老友记 to be nasty to each other.
Just figure out y ur friend is taking ur best friend away & just c what u can do 2 get ur best friend 2 be nice again. No 1 should be treated this way!! It's just terrible!! :'(
If your friend is stealing your friend, and your bestie is being a jerk, they were never your friends. Find some good 老友记 who won't treat 你 like trash. 老友记 你 deserve.