I don’t know who you are, you know that right? That being the case I can’t tell you why. It could be any number of things, including but not limited to…
-It’s a drawing submitted for a different challenge.
-It’s a drawing submitted by someone else before.
-You have been sending it to the wrong inbox and somehow slipped through the cracks.
-Somehow your submission just never got through to us. As in broke in transit.