Thanks for your post, Marc. This is exactly the place where you should come to vent your frustration with a vendor. Umnitza is a member of the forum, so hopefully they will respond here, either pubically or to you via PM.
Just an update to this old thread, I had bought an LED interior light kit from Umnitza. Some bulbs like the map light were simply the wrong size. some did not work and most of them flickered. The ones that did work eventually failed.
After a bunch of back and forth and this initial post they sent me a some new bulbs, They sucked just as bad and at that point I gave up and bought a kit elsewhere that has performed fine.
To be fair I bought a set of wheels from Umnitza and some headlamp bulbs that have all been perfect.