Why do I need a new modem for the unlimited plan? And on that note, how does that work, they send me a new modem and I connect it myself? Do I still have my old service until I get the modem connected. Just thinking ahead as I will probably upgrade in the first part of 2018. The unlimited plans were gone for me a few weeks ago, but are now back, and hopefully still be there when I'm ready to upgrade. Thanks.