Printing Errors or Lights & Stuck Print Jobs

My printer is barely over a year old and barely used. The original cartridges were empty, mostly from printer maintenance tasks, so I bought new cartridges and installed all 4 black and colour cartridges, 902XL (VERY expensive). Since then, the colour cartridges print perfectly, but not even a hint of black ink whatsoever. I followed every step suggested on the HP support page and on the support community forum thread here: 

https://h30434.www3.hp.com/t5/Inkjet-Printing/HP-6978-won-t-print-black-ink/td-p/5922581/page/1

It still prints no black at all and I have wasted about $30 of ink (about 1/3 used from each) from the brand new colour cartridges. I even thought it may have been a faulty black cartridge, so I tried the second black cartridge from my Costco 2-pack (did I mention, VERY expensive?) to no avail. 

I am about ready to take it to the recycling depot and never buy another HP printer. I previously had an 8500 series and had nothing but issues with it, too, having to replace the printhead, and wasting a fortune in ink there, too. I am at my wit's end and will be so angry if this is not fixable within only a few months of the warranty expired and not even getting past the original ink supplied with the unit. 😞

Almost feels like it was set up to fail from the factory, right after the warranty expiration in July! 

Any help greatly appreciated! I have only printed maybe 20 pages from this thing - it's practically brand new!