This is a belated answer so hopefully it can be of use to folks who search for and find this question.
When troubleshooting, always remember that replacement parts are not 100% reliable. Considering the nature of where some of these parts come from, it's surprising things work at all. iFixit offers a much better quality control environment and typically has very low failure rates. However, they do stand behind their products and will gladly offer you a replacement in case of issues.
So if you're replacement screen doesn't work but your original screen does or if you were able to confirm this by installing them in another device, then contact the vendor for a warranty replacement.