+1 for the CC dispute
Just call your issuer (bank) and not Visa, MC, Amex etc. Have everything documented from order info (date, amount, merchant info, etc) to attempted contact info. Your issuer will probably want you to attempt to contact them via phone before they do any work. Just make sure you note when you tried to contact the merchant. Depending on your standing with the issuing bank and if you have history of disputes, most likely they'll reverse the charges.