Really sorry to hear your bad experience. Light shops if you don't really know them don't purchase from them especially first time.As for my personal experience I will buy one or two light from 1 shop and see how it goes. If really ok than will go for big purchase. Few years back I had to buy light for my whole house which is a double story, is so many lights and all. Same thing I had no way to check. Good thing is a very reliable shop, any problem change 1 to 1 without any question ask. Broken or missing piece is replace without question ask as well. This are the kind of shop will make people go back to again.

There are many people not aware and just buy because they see what they like.

Forgot the name. Is in Puchong

There is no full proof way of renovation being perfect. So is just have proper expectation. I had done exactly like what you did all by myself. Is really lots of problem because of busy schedule. Lucky thing is I had 1-2 hours a day to check the reno myself. No joke, is everyday I also check. This time going to do reno again even on a more major scale, so I decided to get main contractor and ID to do everything. I will just go and check. Keep a close watch will be able to change if things is not right from the start.