I assume they are not getting too hot and they are getting watered as the compost dries out.
I've checked mine in the greenhouse today and one is only just showing signs of life although the others have a good inch of leaf growth. So they may be a little slow I'd wait a week or two longer before assuming they are dead.

Watering and warmth and they should be growing up by now. How deeply did you plant them and did they feel firm when you planted the corms?

Planted indoors or outdoors? If outdoors, what are your temperatures like right now, day and night time?

They are dozy things. Don't give up.