Half.com I order one book on this web site, But they charge me twice and i am trying to send email to them but they don't respond back to a cancellation. I talk to one of my banker to cancel the transaction i Internet

I bought a book in half.com and I haven't received because i don't want it. The reason I don't want it is because i was charged twice for one item. I have send emails to them but their response is not explicit. I think they ignore my issue I have against them. I also call e-bay because supposely is an e-bay company. they said they can't help me with that. Then "Why do they put in their site that half.com is an e-bay company. I am willing to receive information and share information to all those people that haven't receive the good service through this company. Half.com has get money from my card withou my athorization. In my half account appears that i buy one item. but in my bank account appears that they charged me twice the same quantity. Hope the people from goverment who inspect the anti-fraud companies can get rid of companies like half.com.