QLN320 bluetooth stopped working

Hi All, i have a QLN320 that the bluetooth has stopped working, i have done all the usual, configuration, reset, different batteries. It looks like the bluetooth is dead. This is actually the third printer i have had that has done the exact same thing, i need to get it back for repair once again. Has anyone else experienced this and if so is there a common cause, given the how expensive these are for what they are i would expect them to last, it never seems that they fail for any other reason other than the bluetooth just goes down. this is what i tried, update firmware to latest version, zebra set up utilities configure printer connectivity all to no avail, shows on the screen that bluetooth is on but no connections, not discoverable on any device