Can the custodial parent be held in violation of parenting rules for not having a phone under Arizona law

Michigan custodial parent has no permanent telephone number for the non custodial parent to phone child. Divorce took place in Arizona, where non custodial parent resides. Would this be a violation of the his parenting rights to reasonable contact with child? In Michigan, when I asked this same question at the friend of the court, I was told that there is no law that states the custodial parent must have a phone, and that if phone contact is wanted, the non custodial parent should provide the phone. Please reply as soon as possible with some sort of an answer. I'm trying to help a friend out that can't afford to hire an attorney and she is starting to panic.