Just wanted to reinforce what dee k. wrote. The US Federal Agencies have no jurisdiction over companies which have no US presence--I used to be a federal investigator. And, independent attorneys can do nothing to support litigation in such cases, not to mention that $300 would not merit an attorney's representation. Had this been a local store, you might have had a shot at a small claims court recovery. I'm not an attorney, so please feel free to double check.
It looks like someone was kind enough to respond really quickly to encourage you to contact your cc company, your best hope.
There are a number of similar scams on the net at present, great looking clothes at well below normal sale prices. Clothes made of better fabrics--soley for the photo shoots--drape better, so, off the top they look more flattering. The same old 'if it looks too good to be true' hasn't changed, but I hope you haven't learned an expensive lesson. I've had some from Neiman Marcus--the worst of any established brick and mortar when purchasing via their online sales, despite their upscale rep and clientele. I suspect we're all in for a rocky ride as the brick and mortar retail stores are rapidly disappearing.