Hi there.
Don't worry if you shop in the client and a message comes up payment unsuccessful and your wallet amount has gone down with no sign of your new stuff.
This has just happened to me twice. I just closed the client down and restarted and what you just bought, appears. (Well it worked for me anyway. Can't see why it won't for everyone else). But, I did buy only one thing at a time though and restarted each time.
I've just tried the online shop and that is ok. Bit of a pain if you are searching for something but it works.