i dont think you can call somebody who backstabs you and uses you for your car a friend.  I say drop them!

Yes , I've met also that kind of person, they pretend as if they are nice to you but when they are not in your presence they make disgusting comment. It can make your nerve stand-out upon hearing it.

You have to be honest to your feelings . Why not explode of what is inside of you , but don't make it in a drastic way.. The two of you must face to face . Confrontation is needed.

In this wide world , we can see the many faces of character in a person. That is why we must not divulged all our secrets to our friend. There must have a self reservation.within us. 

avoid hanging out with, simple as that! they don't deserve your friendship.