RWest sorry to hear you are having problems I have been using devolo for over a year now and not had a single problem links have been rock solid . originally started with the dLAN Highspeed Ethernet but have now upgraded to the dLAN 200.
They have been the simplest most reliable kit I have had the pleasure of using for years, truly plug and play.
I note you say you have usb and ethernet
do you connect by ethernet or usb
heve you contacted devolo with your problem, they have always been very prompt to answer any questions I have put to them.
you may have been unlucky and got a faulty set try exchanging them.