JustDeals.com Sent me faulty item, authorized return, now they won't refund or exchange. Internet

I purchased a refurbished Sylvania 7" Wireless Mobile Internet Device back in June and as soon as I received it I opened it but they had either sent me the wrong charging cord or the unit was defective because I could not even plug it in to verify that it worked., I had purchased this through mypoints.com and immeditely contacted them to find out what I needed to do. I was given the run around for 2 months. I was told mypoints was getting in contact with justdeals, that justdeals did not have an inbound customer service center and that I should just wait. I emailed a couple times a week and finally was given an RMA#. I sent the item back to them at my expense immeditely and they had it within 3 days. It took 2 weeks before I heard from anyone and the response I received was from Marcus at justdeals.com. He sent me an email advising that his supervisor had denied my exchange. I called Marcus and he said although they would not exchange the item he would get a reund out to me and I should have it within 2 weeks. After 2 weeks passed I called Marcus again and he again stated that he would have the check sent right out to me and I should have it in 2 weeks. 2 more weeks passes and I call him again, he is sending it. Marcus seems very understanding on the phone and I have been very patient with him up to this point. Of coarse it has been 2 more weeks and I still have nothing. I don't understand whi they would authorize the return and THEN tell me they won't accept it. I have emailed Marcus numerous times and even left him voicemails but he is very hard to reach. They have had their netbook back for 2 months now and I am still trying to get my refund.