Then that's your key. Key has three separate functions. Normal key that starts the car, this is the one that works. Remote lock/unlock, this is separate. Then keyless go. They are not interlinked, separate.
Get new key. Won't be cheap, but it'll restore it.
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!