Hi chocolotize,
I haven't had any personal experience using this site but they do seem quite legit and they offer a safe payment method - PayPal.
I did a quick background check for you, they have been online for a little over 2 years. I wasn't able to find any negative comments about them. In fact, I was able to find a number of positive comments on other forums. It should be pretty safe to deal with them just make sure that you use PayPal when you order and avoid any products that are offered as branded.
Also here are two suppliers that have corsets, you may want to check them out:
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All the best! :)