You shouldn't stop communicating with a friend.
John and Dave have been friends for many years now, but they've started becoming increasingly busy in their lives.
John wants to focus on his own life.
John tries his best to keep in touch with Dave despite his busy schedule.
John stops contacting Dave and does not return any calls.
John manages to maintain a wonderful friendship with Dave.
John and Dave start drifting apart to the point where they are no longer friends.