TiVo Stopped Working: Channel Not Authorized (V58)

Hello. One of my TiVos stopped working, displaying the message that the channel is not authorized and that I should contact my cable company. So I did, and ultimately learned, after 2 or 3 calls and a visit by a tech, that cable cards are no longer supported by Xfinity, and that my TiVo was obsolete. One person, the only person who was knowledgeable about cable cards, said I needed a new one, and dispatched the tech I mentioned above. The card seems to be paired correctly. I'm at a loss as to what to do now. Scare up a card on eBay myself? Any advise will be appreciated. We would miss our TiVo sorely! Thanks, Mike