Dell Optiplex 7050 Micro 256GB Desktop

On December 5th we notified the seller that the unit was not functional and going into shutdown mode. His solution was for us to fix his faulty product. He did send us the part, however the machine again failed. Again he asked us to repair it, sending us a $20 credit to find our own part as he had none available, yet again the machine continued to go into shutdown mode. After several attempts to reach the seller both through the Amazon message center and the email provided on his customer profile page the seller never responded. I filed a claim against the seller. Amazon even gave him a 48hr time to respond to them in which he did not, I gave him an additional 48hrs, still no response so a refund was requested, he magically appeared and requested me drop the request and guess what AGAIN he wanted us to fix his faulty product. He then proceeded to tell Amazon he would replace the item not mentioning to them it was only the part he wanted to replace that we have already replaced 2Xs he wanted to send us... not and entire functioning unit. I appealed the claim as I felt he lied to Amazon to get them to drop the request. Then he appeals stating it is out of the return/refund window. IF HE HAD DONE THE RIGHT THING ON DECEMBER 5th it would not have been. He gives Amazon a tracking # around February 5th for the part he wants us to replace for a 3rd attempt and guess what it is now February 21st and the tracking shows it has not even shipped. He claims it is because he is moving offices...I am too and my customers are still my priority. I have again appealed the claim and hope the seller does what is morally and ethically right as a seller and just give us a refund so we can purchase a functioning unit.