I'm starting to suspect the root cause of many of the issues with the dock (usb ports and ethernet not recognized, not charging) is the pin connector socket on the laptop. It's really not a great design to start with - you can wiggle it and it disconnects which is pretty scary - and I'm pretty sure if the pins aren't making good contact, things are going to fail. This also may be why Msft has been so unresponsive because recalling hundreds of thousands of Surfaces would be a disaster for them. I know they were trying to be clever with the magnetic connector but to me it's a weak link and should've been made much more resilient.
thats the game they play - being unresponsive or sending people in circles
there are several serious well-documented defects going back two years
they still sell the product even though it has unresolved defects
its disgusting