I think you use incorrect terminology and perhaps you misunderstood how the stuffs work.
If you use lec/les/lep commands then you use shell on either Tag or Listener node. It has nothing to do with MQTT and topics.
If you want to use MQTT, then you need to get the Gateway running and then use e.g. mosquitto_sub to record the data. The topic can be printed also using that command. See its manual.
There have been a quite few posts discussing this, e.g.: