Pardon my cynicism, but this "challenge" follows the time-honored pattern of solving a coding problem by pretending it's a contest, then exploiting the results for private gain. In the right-hand column of the web page, we find "We're hiring Web engineers ..." No, really? Color me surprised.
We are not trying to be sneaky here. Our engineering team is actually the one that came up with the idea. We are hiring and we are definitely doing it in a fun way.
Yes, and the proof of your good intentions is that you posted the contest's conditions on your Web page -- the licensing and disposition of the contest entries, the awards if any, and so forth. The fact that these essentials are missing was an oversight?
> Our engineering team is actually the one that came up with the idea.
Your social engineering team?
> We are hiring and we are definitely doing it in a fun way.
No contest conditions = no fun. Those are the rules.
All you're telling me is that you're inexperienced in running a business. Take this opportunity to show that you understand the modern world -- fix the contest content of your Web page. Explain what it means, where the contest entries go, who owns them and so forth.