An AT&T customer support person told me today that my GPS (even with their AT&T Navigator) will not work with my current SIM card. I have an orange 64K SIM card (63513G) and connect to 3G and HSPDA. Do I really need a new one or they just trying to force me to get a new data plan. I have an ancient plan called Media Max (pre smart phone plan) with unlimited data and do not want to change. Thanks in advance for any advice.