Surface Pro 4 type cover suddenly not working.

I understand your total frustration.  As silly as it sounds, here's my fix.  I started with the dead keyboard connected and powered up, went went to conrol panel/devices and removed the keyboard driver.  Then I detached the keyboard and rebooted.  When the reboot was finished, I reattached the keyboard.  Rather than reinstall the old, corrupt driver, Win10 found a driver (I don't know if it was the same or updated but it was different than the resident corrupt driver, checksum) and installed it.  Mine has been working ever since.  This is one of those procedural things that they don't tell you in the fine print and you're just supposed to know them.  Jack Daniels make the whole thing better.

did a factory reset fresh install, updated all drivers,  updated to build 1903,  keyboard still dead.  so fed up of hopes to have it fixed. 

Anyone kick off a class action lawsuit against MS I'm definitely in

Did everything possible. Still dead. Key pad itself ok, tried on another SP4 and it works. Tried a new keypad on mine and it doesnt work. So either firmware or hardware (motherboard). Im fed up with MS. Using a BT keypad now or sometimes the touch screen. The keypad doesnt even appear in the Device Manager.

did a factory reset fresh install, updated all drivers,  updated to build 1903,  keyboard still dead.  so fed up of hopes to have it fixed. 

Anyone kick off a class action lawsuit against MS I'm definitely in

If Microsoft had a version that specifically lacked the problem, it would be nice.  People have gotten replacements that ended up doing the same thing, sadly.  I don't look at it as a hardware problem but as a firmware issue that's causing incompatibility with the hardware.  The worst part is the same company makes both the hardware and the firmware and drivers, so they have less of an excuse than others would.  I'm still hoping a fix shows up (a real fix, not being forced to pay for new hardware), but I'm not optimistic.  We do have lemon laws here, but since this isn't happening to the vast majority of owners, the most we can do about it is nag Microsoft about it or file a class action.  Formally acknowledging the issue would make us afflicted owners feel more respected as opposed to the "Oh well, try your luck with another and see what happens" response most of us have received.

In that instance, wouldn't it make it a hardware issue?  -Independant of the firmware.

It can be either cause. Not trying to argue, but what the MS guy said still rings true of it being either or.

I don't know what the laws are in USA, but consumer wise here, independant of the warranty, there is still an expected lifetime of a product that a retailer would have to replace a faulty product under. But electronics these days 2-3yrs anyway?