How to protect my designs as it happens in the marketplace

I’ve just opened my shop and I’ve got some designs in the Marketplace as well. Unfortunately, I’ve just noticed that there’s no way I can protect my designs in my shop, I mean, anyone can download them and there is no watermark as it happens in the Marketplace. Why?
I don’t feel like keeping my shop open on these conditions, hope you can find a way to fix it.
Thanks in advance,