Netflorist refusing to refund

Netflorist duplicated a payment on my credit card. Despite numerous (unanswered emails), they have yet to refund me. I want my money refunded and them to have the courtesy of responding to my emails. When I called I was given a name to which to address my email, giving details of the erroneous charge. I did all this, yet I have not heard any further from them. This is ***** to double charge a client.