I am unable to receive calls
If you are unable to receive calls, check that the correct mobile number has been given. It is also possible that a Divert may have been sent to Voice Mail box. In such a case, Call/Mail the Network and get the Voice Mail deactivated by dialing ##002#
If you face this problem some time later after using the services, there is a possibility that the SIM card has got damaged/corrupted. In such a situation the SIM card will be delivered to you at the international location.