A relay device comprising: a communication interface and a processor for relaying messages, via the communication interface, between a communication device and service devices, the processor enabled to: determine that a subset of the service devices are available after being unavailable; and, in response, block incoming messages associated with the subset of the service devices, the incoming messages being from the communication device and for transmission to the subset of the service devices; and characterized by: after the incoming messages are blocked: stop blocking the incoming messages associated with one or more of the subset of service devices after receiving a plurality of indications to relay messages respectively associated with the each of the service devices in the subset, the plurality of indications received one after the other from an administrative device, wherein the order in which the plurality of indications are transmitted by the administrative device or received by the relay device is dependent on when the administrative device makes a determination as to when a volume of messages associated with a given service device of the subset of service devices falls below a threshold value, and wherein stop blocking the incoming messages associated with one or more of the subset of service devices is in a priority order of the subset of service devices regardless of which indication of the plurality of indications is received first such that the incoming messages are relayed to a service device of the subset of the service devices having a higher priority before being relayed to another service device of the subset of service devices having a lower priority. a communication interface and a processor for relaying messages, via the communication interface, between a communication device and service devices, the processor enabled to: determine that a subset of the service devices are available after being unavailable; and, in response, block incoming messages associated with the subset of the service devices, the incoming messages being from the communication device and for transmission to the subset of the service devices; and determine that a subset of the service devices are available after being unavailable; and, in response, block incoming messages associated with the subset of the service devices, the incoming messages being from the communication device and for transmission to the subset of the service devices; and after the incoming messages are blocked: stop blocking the incoming messages associated with one or more of the subset of service devices after receiving a plurality of indications to relay messages respectively associated with the each of the service devices in the subset, the plurality of indications received one after the other from an administrative device, wherein the order in which the plurality of indications are transmitted by the administrative device or received by the relay device is dependent on when the administrative device makes a determination as to when a volume of messages associated with a given service device of the subset of service devices falls below a threshold value, and wherein stop blocking the incoming messages associated with one or more of the subset of service devices is in a priority order of the subset of service devices regardless of which indication of the plurality of indications is received first such that the incoming messages are relayed to a service device of the subset of the service devices having a higher priority before being relayed to another service device of the subset of service devices having a lower priority. stop blocking the incoming messages associated with one or more of the subset of service devices after receiving a plurality of indications to relay messages respectively associated with the each of the service devices in the subset, the plurality of indications received one after the other from an administrative device, wherein the order in which the plurality of indications are transmitted by the administrative device or received by the relay device is dependent on when the administrative device makes a determination as to when a volume of messages associated with a given service device of the subset of service devices falls below a threshold value, and wherein stop blocking the incoming messages associated with one or more of the subset of service devices is in a priority order of the subset of service devices regardless of which indication of the plurality of indications is received first such that the incoming messages are relayed to a service device of the subset of the service devices having a higher priority before being relayed to another service device of the subset of service devices having a lower priority.