I purchased a used RCA DirecTiVo DVR40 on Craigslist. I called directv and they sent me a new access card for it. I then called them and the box is able to recieve programming. However, I can't use the DVR functionality on the unit. Several calls back to customer service have been unsuccessful. They have had me reset the box several times, remove and insert the access card. No help. On my own I tried "clear and delete everything" and still no help. Any ideas?