Refund authorized

I am very disappointed. I have bought a new notebook and I have received a second hand. It was sent to technical assistance and the problem was the mainboard. Unbelievable! After a very long process, many emails going back and forth, I have just realized my call is closed. Nobody wants to talk to me on the phone. This is not the kind of assistance I would expect from Dell. Would someone help me in? I just want to send you the notebook back and have my money back wich is already authorized by Dell Brazil.

I live in Brazil. I am sure if I lived in the USA this would not be the treatment I would receive. Thank you