I just switched to T mobile and am getting 3 lines and wanted to get the phone from my sons mother who is a T mobile client to put on my new line but T mobile said that number can't be ported form T mobile to T mobile even if she cancels that line. They said we would have to add a 4th line and pay 35 dollars for that line. Does anyone know a solution for this or the rules for this? thanks for you help and time