A mobile communications device receives an indication of a balance from a server when establishment of a voice call or sending of a message is requested. The mobile communications device determines whether the balance is sufficient to place the voice call or send the message over a mobile network. If the balance is sufficient to place the voice call or send the message over the mobile network, the voice call is established or the message is sent under normal operating conditions. If the balance is insufficient to place the voice call or send the message over the mobile network, a grace period is activated and the voice call is established or the message is sent during the grace period over an available wireless local-area network.