Hi there,
I hear the frustration and can totally understand, I’m surprised the vid & Pid are all Zero’s too… that is a new one. You gave it everything so it is perplexing to say the least. 
A return may be in order , tell them we worked with you on the support forum to grease the slide and get replacements.
Before you send them, try a different physical USB port on your computer please, then if at all possible another machine.
after a fresh reboot what does the Device manager say in the Drivers tab. I’m afraid without a Vid or Pid windows won’t know what to enumerate to.
FYI , ZADIG is great but you can mess up your system if your not careful, so go slowly using it.
If you had a J-Link device you could troubleshoot further but Not really the beginner or new user starting point for sure.
You have tried other cables also ? Something has got to be off configuration wise ? I fear you’ll get new units and the same situation might exist, hopefully NOT 
is the Windows updated?
HTH
GL 
PJ 
Can you remove the com port from the device manager, reboot with Xiao connected (use a physically different USB port if possible) can you describe how your system is ? what type?