Where can I find a screen for my Kobo Sage

Hi,

The screen of my kobo sage was broken 3-days ago. As the rest of the device works perfectly, I would like to change the screen, but I can not find the piece anywhere. I have tried Ebay, Aliexpress, Ifixit. I even tried the seller of the kobo (FNAC) but apparently they can't even do the fixing themselves because they don't have the square part. So far for their "user-repairable" ad...

So anyway, I'm out of ideas as to where to look, so if anyone could give me a hint on where to find a new screen, that would be greatly appreciated.