lose contact with
lose contact (with one)
To unintentionally decrease frequency of communication (with one) over time until no further contact takes place. Unfortunately, my college roommate and I lost contact over the years, so I have no idea how she's doing now. I lost contact with Tina after she moved to Alaska. The last I heard, she was still living out there.
lose contact with someone or somethingand lose touch with someone or something
[for communication with someone or a group] to fail or fade away; to let one's friendship or relationship with someone or a group lapse. I hope I don't lose contact with you. I don't want to lose touch with my old friends.