I signed up to a website for the purpose of receiving web hosting. It was supposed to be a free service but I've received invoices for over $160USD. The invoices state that the charges are for volume and has been billed at the rate of "278.06111 Hour". The problem is that the type of web hosting offered by this service was too technical for me, so I never actually got a website stored on their servers, therefore I don't understand what "volume" I've been using. What can I do under Australian Consumer Law to get this company - which is in Panama - to stop invoicing me?