I purchased some Restaurant.com certificates a while ago (in 2011). I don't think any of these restaurants are still offering certificates on the site; will I still be able to use them? I know I can exchange them, but I certainly don't want to find that out AFTER I make the effort to go to a specific restaurant! I guess I could call or email each restaurant beforehand but that seems like a royal PITA and I'm not even sure the person answering the phones could give me an accurate answer. Anyone have experience with this?