Invalid serial number for 2016 WN3000RPV3

I am trying to set up a range extender I purchased through Amazom in 2016.  It has never worked, so I'm finally trying to figure out how to do this now that I need to work from home.  The serial number (a 12 digit one)  is not recognized, my security question answers are not recognized (I'm sure I know my oldest and youngest brothers' names!), therefore I can't set up a case, and the current wait time on the phone is 1.5 hours.  Why is this so difficult?  (I recognize this is an extraordinary time in history and a lot of people are in the same boat as I am.). Thank you for your help.