MQTT not acquiring all information

Hi, I have openhab on RPi with Mosquito MQTT messaging.
However, there is data being ignored/lost it seems when MQTT is busy, i.e. it won’t accept new data coming in from sensors for example.
Is there a way to make sure that data comes through and is say queued so it gets through the broker to openhab? I have looked at pubsub but it doesn’t seem to have qos capability higher than 1,


It is usually better form to only post a question in one place. See my response to your other posting.

Ah yes, sorry… When i realised you had solved the other posting I made a new one, but forgot to remove the other, thanks