In reply to mypyrex:
We always say 3 working days but provided both of your banks are part of the faster payment service (all the big uk banks) it should just be a few hours. Have you given them your bank details? If not then they're not going to transfer it to your bank account they will just put it back on your card and that can take a bit longer. It's worth phoning your bank for advice. Also google "resolver", that's probably your best shot. There's lots of ways to get your money back without hiring a solicitor.
This year I've spent quite a lot of time at work chasing companies that have tried to screw us over in various ways, business to business transactions aren't covered by consumer rights and we're too big to use ombudsmen but not big enough to afford to take on big companies legally which makes it harder. Most have only been solved by getting hold of the company director presonally. If it's a limited company you can find their details online. Linked In is a good place to look also. It's worth quoting the relevant section of your consumer rights when you complain, also read through their terms and conditions (they'll be on their website) and quote their refund policy to them. If they take payments online then it's legally required for them to publicise their refund policy. If they're selling through a third party (ebay etc) then they are bound by their terms and you can complain directly to them. Depending on the company they may have an industry body or an ombudsman you can complain to. I would also make your correspondence with them daily, email followed by phone call. You can also try posting a (polite) message on their facebook page asking about your refund. Don't leave it weeks between contact if possible. If you're a pain in their ass then they'll pay £75 to get rid of you, especially if you sound like you'll cause them problems. I find being polite and factual gives better results than getting angry but just keep at them and you'll get it back.