
Your comments re worldpay are way wide of the mark.
You could have contacted worldpay for a refund and your bank should have also taken more action. The line they span you only really applies to people like paypal who operate in the manner you mention.
My company use worldpay and once or twice a year we get subject to charebacks - only once in 5 years has this been valid - it was a fraudulent transaction - in all other cases the customer simply didn't recognise the transaction.
All you had to do was write to the credit card company asking them to do a charge back and providing copies of the correspondence between you and the company concerned. I've done this myself when I had a problem with a supplier in the USA and the money reappeared within days.
If a charge back is done on Worldpay the retailer gets charged £25, plus the original transaction fees so it is in the retailers interest to refund before the transaction is disputed.
We use worldpay because we don't want to be responsible for the security of your credit cards details. We are quite happy to leave that in the hands of a well recognised quality payment gateway used by 10s of thousands of companies would wide to securely process your card transaction.
Much better to use a site driven by a well known payment company who can therefore verify the company you are buying from actually exists rather than sending your credit card details to some random web site designed to rip you off with no way of tracking them down.
If you buy as you suggest from sites what manage the process themselves then you risk your card details being stored insecurely or transmitted insecurely, take for instance a recent occaision where I booked a hotel online. My full card details were email to me and the hotel in the booking confirmation. The site in question thought this was entirely acceptable even though it stated it used the latest security encryption and was totally secure.
As for stock levels, many, I'd guess most online stores have no true picture of stock levels, so the stock levels are updated as and when the trader does it and between then and them processing the orders it is easy for them to sell out. Clearly this trader was a bit suss as they did not offer a refund as they should and did not provide the refund quickly when asked. Your bad experience was down to a bad trader.
If you are buying from a company you do not know and want some idea whether they are genuine, pick up the phone and ring them. If they don't have a phone number don't touch them. Often the number advertised on fraudulent web sites doesn't exist or belongs to someone else. Check 192.com or companies house for the company concerned and check they exist and are at the address shown.