Thats song is about a fake friendship. It says about two best friends who used to call spend time together help each other. Although when the one left the other one changed she became another person and the other one missed her. Not only did she change she also left her alone she make new friendship and left the other girl completely alone. And that hurts giving all your love to someone trusting them dreaming a life with them and just being replaced and understand that all those was a lie...