Unless you have a really old plan, you shouldn't have any roaming charges now with Verizon Wireless.  Is this location close to the Canadian border?

Are you sure this is a Verizon Wireless tower?  Perhaps it is a tower to support voice and 3G data only instead of 4G.  Have you reset the SIM card since it became operational?  Turn off the iPhone 5 and remove the SIM card for a few minutes.  reassemble and start up the phone again.  This will reset the phone's and the SIM card connection to the Verizon Wireless network.