I had little money there, and they seem, as you said, disappeared without a trace. About a month ago I got a reply to my email, but my return emails do not reach them (get a bounce message). Also sending a letter to their parent company's address did not have any effect (They do not even have any contact details on their own website).
My impression is that they do not want to return the client monies. Of course one could file a complain, but I assume chances of getting one's money back is very slim. Does anybody know if the company was regulated by FSA?