I ordered Fire Emblem: Awakening today before 5pm, but didn't get a dispatch e-mail. I checked my bank and 28.12 has come out. The cost of the game was 27.11 so I don't know what has happened.
I buy a lot of stuff from them (haven't in a while though since they had a system error and couldn't find a pre-order I already paid for), but I don't know what to tell you. Contact the customer support and wait for their answer, that's probably the only thing you can do. Also, their support is usally pretty good. If you didn't get a dispatch mail that simply means that they haven't dispatched it yet, it usually takes them a day or so.
Also you bought it for 27,11 but paid 28,12? I'm guessing that includes shipping? Cause thats still a pretty good deal, seeing how it currently costs about 33 GBP on the site. Did they had an offer or something?
Also is this your first purchase? I don't quite remember how it went, but I think when you first buy something there they charge you 1 GBP top validate your creditcard and pay it right back after it has been validated, not sure if this is what's going on though.