Received Damaged Misrepresented Item through Website Purchase

I ordered a new printer (HP Desktop 460c) from them. When it arrived, it was missing the power adapter and had some damage to the printer. Also the instructions and installation cd appeared to be used. It very much looked like a used or refurbished unit, but I ordered and paid for a new one. Their return policy states a customer wanting to return an item must start a case with the manufacturer before requesting a return merchandise authorization from compubizusa.com. I did that the day after I received the item and sent the information to compubizusa.com requesting the return merchandise authorization number (RMA). They refused stating that the manufacturer (HP) was responsible. I replied that compubizusa.com sent me something I didn't order, a damaged, probably refurbished item that I couldn't even plug in and use since it had no power adapter (which was supposed to be in the box it came in). They have refused to refund my payment and would not let me return the item. I am disputing with my credit card company, but it's been over a month now and I have no satisfaction.