I don't understand why my 3G modem insists it can only connect as a Global Roaming connection that will cost me more than $20/MB for service. I'm in Buckeye, Arizona, outside of Phoenix. It is neither remote, rural, nor in a foreign country. I don't understand why it keeps showing a Global Roaming indicator on screen with a warning saying data service will be charged at $20+ per megabyte. What's going on???