If your ‘Siemens C72’ device displays a “No Service” or an “Emergency Calls” only message, this would usually indicate that you are in a location with poor signal strength / limited network coverage.
As a further test however, we would recommend attempting to select a network manually –
1) Go to the main ‘Menu’ by pressing the center button on the keypad (joystick navigation button in the middle).
2) Select “Setup” (icon shows a picture of a wrench)
3) Select “Network”
4) Highlight “Auto Network” and select “Change” to disable this feature (so that the tick is removed from the tick box).
5) You can then select “Choose Network”, select “Manual” and wait while the phone performs a search.
6) Select a network from the list to connect to and then retest the service.
7) If this resolves the issue, please re-enable the “Auto Network” selection option again when you travel to a new location.