Beautiful fixture but wired incorrectly

We like the look of the fixture but professional installation is highly recommended. First, the instructions are poor in terms of how to adjust the length of the lights. But more importantly, the fixture was wired in reverse!! After I first mounted the fixture, our GFI kept tripping each time I went to turn on the light. I could not figure out why the fixture would trip the GFI since the old fixture did not trip the GFI. So I by passed the GFI and the fixture still did not work. I took down the fixture and wired an outlet to the ceiling wires so I could test the wiring. My outlet tester confirmed the wiring from the ceiling was correct. I then cut an extension cord and wired it to the fixture so I could test the fixture on my work bench. When I went to plug it in, the outlet buzzed and the lights in the house dimmed. I only got as far as just touching the plug to the outlet. So, thinking maybe I screwed up wiring a polarized plug, I switched the wiring and connected the hot wire from the fixture to the neutral (white larger plug) to the cord and the white wire from the fixture to the "hot" plug prong and tried again. Result: It worked!!!! So, I re-hung the fixture (wired it in reverse) and the fixture works great ( after first replacing a fried slight switch as a result of the first time I had installed the fixture). What should have taken maybe an hour took over four hours!!!!!! The fixture looks great but the product as wired (at least mine) was defective and a hazard.