Exim Arts sold my fully paid fountain

I'm so disappointed with Exim Arts. Last Aug, I've bought a 4 Square Pillars step fountain from them, but when its due for delivery in Nov, the fountain never came. Called them to check & was inform that there's no order for delivery on that day. Given them the sale order to trace, they checked & oops.. They have sold the set that I've fully paid for!!

Now that they had refund me, but there's no way we can get the same set again. Anyone know where can find this similar fountain for within $350? Some landscape company that we went to was selling similar design at over $800, some even over $1200.

How could this had happened? Was told by the staff that they had place the order & inform the warehouse, but somehow, it was still sold & even the display set was sold too. So who's at fault? The warehouse release the fountain without checking or the sale staff did not place the order?