I signed up for the 2 year membership from mp3share.us which cost £15 plus £9 for some spyware software that I didn't want.
After reading the posts on this site I realised I'd been scammed, so contacted my bank, who said they wouldn't or couldn't stop the payment and that I'd need to contact the company I'd bought it from.

It was a long shot, but I called the company (long distance) and was amazed when they said they'd give me a full refund! There was an admin charge of £7, but that's way better than the £24 I'd thought I'd lost forever. They sent me a receipt too. They must know they're scamming everyone 'cos they didn't even attempt argue when I asked for my money back.

Now I've just gotta wait til the the money materialises! (And see how much they fleeced me for that phone call to customer services). Watch this space...