New Inseego Mifi Issue

I just got my Inseego Mifi device today.  I did the set up.  Put the sim card in and fired up the device.  It worked for 5 minutes before I got an alert that said Invalid Sim.  I rebooted the device to get a "no service" alert.  I had another sim card so I put that one in and activated it and dealt with the same thing.  So I called tech support.  I went through a process of rebooting.  Then was told to pull out the sim, put it back in then hit reset.  This seemed to work but only for 15 minutes.  So this time I went through the process of pulling the sim card out putting it back in then turn on the device.  This time it worked for an hour before I got the invalid sim alert again.  I rebooted to get the no service alert.  Did the who thing over again to have it work for 5 minutes before the invalid sim alert.  Reboot.  No service.  This is not a cheap device so I'm getting really frustrated.  What is up with this thing?