New Laptop Screen is Very Dark, but the old, broken screen was very bright and “worked”

As the title says, I replaced my old, broken screen with a new screen that I purchased from The old screen was totally broken; it had a black line through the center and the screen was completely white. I knew the laptop still worked because I connected it to an external monitor and was able to use it normally. So, I ordered a replacement screen from and installed it. When I installed it, the screen became very dark to the point where I could only barely see it if I hold up a flashlight to the screen. I wondered if it was a problem with the new screen or with the laptop, so I put the old broken screen back in and the screen was still a bright white. Because of this, I think that my new screen is defective. Thoughts? Should I contact the website to see if I can get a replacement or refund? Laptop model is a Dell Vostro 3750.

TL;DR -> New laptop screen very dark, old screen very bright, why new screen very dark? defective screen?