It's ok, you can just have a itch.io page, pointing to the external website and with a note about it. Try fixing it tho, contact them, they are helpful :)
I changed the game file in the project page to do just that now and made the project publicly visible, but I don't think it ever got added to the 7DRL submission list, even though I created the project page yesterday before the deadline by clicking on the submit button on the main jam page? At least I'm not seeing it in the list of submissions. It should be https://viila.itch.io/x001-infiltrator