A method includes setting an account value of an account to a first amount, wherein the first amount is associated with a specified level of authorized usage of a phone associated with the account. The method further includes blocking an incoming call intended for the phone when the account value is at a second amount that is at or lower than a predetermined threshold amount, wherein the second amount is associated with available usage of the phone. A data processing system includes a triggering module to generate a trigger signal when an account value of an account is at or lower than a predetermined reserve amount, greater than zero wherein the account value is associated with authorized usage of a phone associated with the account and a blocking module to block an incoming call to the phone in response to the trigger signal.