Hewlett Packard HP HP drags feet and fails to pay $20 rebates for toner cartridges purchased on same invoice as compatible HP printer Nationwide

On July 15, 2015 I shopped for and purchased an LaserJet Pro M277dw Color All-in-One Laser Printer.   I was attracted to this model by positive reviews, plus mention on the retailer's website of a $20 rebate per additional toner cartridge (up to 4) purchased at the same time.   I bought the printer, square trade insurance on it, and the 4 additional toner cartridges (Black, Cyan, Magenta and Yellow).   Upon receiving the printer and addiional toner cartridges I filled out HP's rebate form, double checked all details, and mailed it.  

The rebate form: http://promotions.newegg.com/hp/15-1522/index.html?icid=311409 (B&H no longer serves it up)

We did not hear back from HP until September, at which time they claimed I had not made a qualifying purchase.   I then replied to their message with all documentation involved in the purchase plus photos of the purchased items.  HP then replied with an email stating that the rebate was being processed, however here we are, it's January 2016, and no rebate!