Many individuals including myself just tried to purchase http://www.roblox.com/item.aspx?id=341110180&rbxp=48103520 and it took our robux (1,000) and we did not get the product. It does not show up in the purchase history either.
I had to purchase it a 2nd time, making my total 2k for just the 1k item, and finally got it.
Check the comments on the item I linked for individuals complaining.
Originally 700 in stock, and only 586 were sold?
Apparently this happened to people who tried to purchase https://www.roblox.com/Living-Art-Number-Four-item?id=335134238 as well.