Disclaimer: I don't work for iFixit and my only relationship is as a customer and occasional contributor.
If you look on the very first page of the iFixit Parts page, they go into great detail about their lifetime warranty. So according to that, you shouldn't have any trouble getting a replacement or refund, at least in the United States. You'll have to check the EU store for the European warranty policy though, if that's appropriate.
For US customers, contact [link|https://help.ifixit.com/article/136-email-support|iFixit Support|new_window=true] for help with your warranty. All of the screens they sell for your phone specifically state that they come with a lifetime warranty; i.e., for as long as you own the phone.