I do not know what is or is not legal under the circumstances. I do not necessarily think based on the information that you have presented that they are doing anything illegal or will do anything illegal. I also do not know whether they will or must refund your money if you ask for it back. That said, think about a few scenarios:
Survive! files for bankruptcy protection. Where is your money now and will you ever get it back? Will it even be worth trying to get it back at that point? Or they have somehow, in the hustle and bustle of rapidly successful company growth, misplaced or lost your order. What then? What proof will you even have that they ever received your money (which by the way is different than your proof that you sent the money). How about they say, "Hey, you want your money back? Sure, that's cool. However, 25% of your up-front payment is non-refundable as a penalty." Or, "Sure, we'll get that refund right out to you" and then they drag their feet until you finally give up.
I think you get it. The possibilities for a bad outcome are endless. Again, I'm not saying that is where this will end up, but in my line of work, I see this kind of stuff go on literally all day long. Sobering to say the least.
Good luck with whatever path you take.