Seller sounds a bit shady. A month? In this modern day and age anything can be anywhere on the planet in 2-3 days if you pay the expedited fee, 5 days for priority and a week to 10 day for slow method. Had one put this on me before and I demanded the tracking info which they refused to provide. When I picked it up I told them I needed the box it came it for insurance purposes, the tracking was still on it. They waited 3 weeks before ordering and had it in 3 days. Didnt help me get it any faster but they reduced the price 20% after I threatened to smear them on social media with the evidence.
Keyboard back-lights could be a bad install on their part or a fault with the motherboard. I have no issues with the lastest version of windows 10 after uninstalling APK, wiping the registry values with Ccleaner and reinstalling whatever the lastest APK package is.
When you say you upgraded the chipset did you do this after the fact? This in and of itself will cause a myraid of problems. Just like this. Chipset drivers should only be installed as the very first thing following the windows install follwed by ME interface. after that then its whatever. I usually do graphics, then sound followed by everything else.

“Two things are infinite: the universe and human stupidity, I'm not sure about the former” ~ Albert Einstein