OK, so, sadly, we ARE talking about the same shop... I'm very sorry for you and I know exactly how you're feeling and I know exactly the type of people you're dealing with.
Here's my advice: don't believe in Mr. X's promises and don't wait any longer. Get a lawyer to send them a letter NOW. That's the only way it worked for me. Before that, I waited for four months and nothing happened. It was the same story: promises, lies and lots of waiting. Then no contact whatsoever. Once he got the lawyer's letter, he transfered the money straight away.
The letter costed me 200 CHF, but Mr. X's bad math skills payed me back...

Maybe you're also lucky or maybe you find a cheaper lawyer... btw, do you live in Swizerland?
The important thing is to make sure to send this letter to their "official" address AND their "real" address (you can find it on the yellow pages, it's in Wollerau).
And don't forget to spread the word about it. Report your problem to Toppreise.ch (or wherever site you found this shop), Kassensturz, econsumer.gov and the State Secretariat for Economic Affairs (SECO):
> Mr. Guido Sutter, Legal Affairs
> Tel. +41 (0)31 322 28 14, Fax +41 (0)31 324 09 56
> fair-business @
seco.admin.ch
>
> SECO represents Switzerland at the International Consumer Protection and Enforcement Network (ICPEN). ICPEN is a network of governmental organizations involved in the enforcement of fair trade practice laws and other consumer protection activities. SECO may act legally, in order to protect Switzerland 's international reputation.
I would also encourage you to visit Kassensturz's forum and leave a few words there:
http://www2.sf.tv/sf1/kassensturz/in.../forum_3_1.php