I also had this problem with BM calling the kids on a constant basis. We set that she can call between 7 and 8 pm every evening and the kids know that this is their time if they choose to call her if she doesn't call them first. We also allow them to call her on the big holidays during the day but that is her call for the day. She was not happy with this rule when it was put in place but after being told by the courts our house our rules she has pretty much abided by it. Doesn't mean she likes it and every one in a while will try to get froggy and jump but I just calmly remind her what the courts said about this issue.. If she tries to call any time other than that it goes to voicemail and the kids listen to it later.. I also keep thier phone in the kitchen in the same place so if they choose to call her at 7 pm they know where the phone is.