Hi

Sounds like you are out of luck locking the car. BUT let me give some options. First I have three keys (long story) but it came into the dealership in 2 days. It came from Dallas. So 2 weeks sounds like BS. All they need is your VIN and proof of ownership -- title or registration. In my case they just did it with the VIN since they knew me and the car.

You may want to take your car and the key to a locksmith and have them look at the key and lock to see why it is Not working. Did it work with the other key or is this a new problem? Maybe the problem is with the lock and not the key?

Did you change the batteries in the key. It takes 2 and you must change both. You can get them at Wal-Mart. I think I paid $5. I carry spares with me in the car along with my plugs for tires.

Don't think a slim jim will not work because the locks are not electric. Remember it is a Mercedes.

Hope this helps.