When they go to the customer!? ... they do not pub...

When they go to the customer!? ... they do not publish a number, there is no contact, I want to cancel a purchase and the system does not leave me if I do not receive the product first ... I already spoke with the seller and the product does not work for me ! ... you will never send it to me, I don't want it, I can't cancel. I have no one to call, the page just tells me to talk to the seller.